Citation
Analog emulation and integration in the hybrid studio

Material Information

Title:
Analog emulation and integration in the hybrid studio
Creator:
Hidalgo, Joseph Michael ( author )
Place of Publication:
Denver, Colo.
Publisher:
University of Colorado Denver
Publication Date:
Language:
English
Physical Description:
1 electronic file (83 pages). : ;

Thesis/Dissertation Information

Degree:
Master's ( Master of Science)
Degree Grantor:
University of Colorado Denver
Degree Divisions:
Department of Music and Entertainment Industry Studies, CU Denver
Degree Disciplines:
Recording Arts
Committee Chair:
Bregitzer, Lorne
Committee Members:
Bird, Leslie Gaston
Krause, Doug

Subjects

Subjects / Keywords:
Sound -- Recording and reproducing -- Digital techniques ( lcsh )
Genre:
bibliography ( marcgt )
theses ( marcgt )
non-fiction ( marcgt )

Notes

Review:
This portfolio examines a practical approach to analog and digital hybrid recording. Comprehensive research is included to determine the advantages and disadvantages of each recording medium including a detailed history of each format. Analog integration in the project studio is research in depth to determine practicality for the home studio engineer, including detailed research on modular recording hardware. Various Mixing techniques including missing in the box versus mixing out of the box and analog summing versus digital summing are also analyzed. Analog tape software plug-in and hardware emulation is examined to determine how accurate through the use of software plug-ins and analog hardware. To conduct this study, a simultaneous analog and digital recording of an acoustic drum kit was produced in order to compare a true analog tape recording and a digital recording modified through the use of analog hardware and software plug-ins.
Thesis:
Thesis (M.S.)--University of Colorado Denver. Recording arts
Bibliography:
Includes bibliographic references.
System Details:
System requirements: Adobe Reader.
General Note:
College of Arts and Media
Statement of Responsibility:
by Joseph Michael Hidalgo.

Record Information

Source Institution:
University of Colorado Denver
Holding Location:
Auraria Library
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
891592856 ( OCLC )
ocn891592856

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Full Text
ANALOG EMULATION AND INTEGRATION IN THE HYBRID STUDIO
By
JOSEPH MICHAEL HIDALGO
B.S., University of Colorado Denver, 2010
A thesis submitted to the
Faculty of the Graduate School of the
University of Colorado in partial fulfillment
of the requirements for the degree of
Master of Science
Recording Arts
2013


This thesis for the Master of Science degree by
Joseph Michael Hidalgo
has been approved for the
Recording Arts Program
by
Lome Bregitzer, Chair
Leslie Gaston Bird
Doug Krause
11/15/13
li


Hidalgo, Joseph, Michael (M.S., Recording Arts)
Analog Emulation and Integration in the Hybrid Studio
Thesis directed by Professor Lome Bregitzer.
ABSTRACT
This portfolio examines a practical approach to analog and digital hybrid
recording. Comprehensive research is included to determine the advantages and
disadvantages of each recording medium including a detailed history of each format.
Analog integration in the project studio is researched in depth to determine practicality
for the home studio engineer, including detailed research on modular recording hardware.
Various mixing techniques including mixing in the box versus mixing out of the box and
analog summing versus digital summing are also analyzed. Analog tape software plug-in
and hardware emulation is examined to determine how accurate analog tape emulation
actually is, including what elements can and cannot be reproduced through the use of
software plug-ins and analog hardware. To conduct this study, a simultaneous analog and
digital recording of an acoustic drum kit was produced in order to compare a true analog
tape recording and a digital recording modified through the use of analog hardware and
software plug-ins.
The form and content of this abstract are approved. I recommend its publication.
Approved: Lome Bregitzer


DEDICATION
I dedicate this work to my mother and father, Michele and Greg Hidalgo. It was
with their guidance, advice, love and support that I was able to complete this portfolio.
IV


ACKNOWLEDGMENTS
I would like to thank Max Boyd, Matt Best, Dan Gilbert and Dan Galanski for
being a part of this project. I would also like to recognize the MEIS faculty and
specifically Lome Bregitzer, Leslie Gaston Bird and Doug Krause for their support and
inspiration over the years. Lastly, I would like to thank my grandparents, Esperanza and
Zaragoza Hidalgo, Stephanie and Garrett Brown, and Monicque Aragon.


TABLE OF CONTENTS
CHAPTER
I. INTRODUCTION..............................................................1
History......................................................................1
Birth of Magnetic Recording..................................................1
Basic Components of Analog Tape..............................................2
Advantages of Analog Recording...............................................3
Disadvantages of Analog Recording............................................6
Digital Recording............................................................8
Stationary-Head Transport Versus Rotary Head Transport................8
Digital Audio Stationary Head, Pro-Digi, and Digital Compact Cassette.9
AD AT Recorders.......................................................9
The Digital Audio Workstation........................................10
Basic Components of Digital Audio...........................................10
Sampling.............................................................11
The Nyquist Theorem..................................................11
Quantization.........................................................11
Advantages of Digital Recording.............................................12
Disadvantages of Digital Recording..........................................13
The Analog and Digital Hybrid Studio........................................15
Analog Integration in the Project or Home Studio............................16
Modular Systems......................................................16
Analog Integration in the Recording Process.................................19
Modern Examples of Analog Recording.........................................22
Analog Integration in the Mixing and Mastering Process......................24
vi


Analog Summing Versus Digital Summing..........................25
Mixing In The Box Versus Out Of The Box........................27
II. METHODS..........................................................30
Purpose of the Study.................................................30
Overview.............................................................30
Analog Tape/Pro Tools Specifications.................................30
Tracking Procedures..................................................32
Analog Tape Emulation................................................51
Slate Digital Virtual Tape Machines Plug-In..........................51
Rupert Neve Designs 5042/542...................................54
Post Tracking Procedures.............................................55
III RESULTS..........................................................64
IV. CONCLUSIONS......................................................67
Other Factors To Consider............................................67
Final Thoughts.......................................................67
REFERENCES...........................................................70
vii


Table
LIST OF TABLES
LI Equipment Used At Colorado Sound (7/15-7/16)...................................50
II1 Equipment List For Tape Emulation.............................................56
viii


Figure
LIST OF FIGURES
LI Kick Drum Microphone Placement..........................................33
1.2 Kick Drum Microphone (Inside Drum Shell) Close Up......................33
1.3 Snare Drum Microphone Placement (Bottom)...............................34
1.4 Snare Drum Microphone Placement (Top)..................................35
1.5 Tom Microphone Placement Angle 1(Top)..................................36
1.6 Floor Tom Microphone Placement Close Up (Top)..........................37
1.7 Floor Tom Microphone Placement Close Up (Bottom).......................37
1.8 Large Rack Tom Microphone Placement Close Up (Top).....................38
1.9 Small Rack Tom Microphone Placement Close Up (Top).....................38
110 Ssmall Rack Tom Microphone Placement Close Up (Bottom)................39
111 Large Rack Tom Microphone Placement Close Up (Bottom).................39
112 Tom Microphone Placement Angle 2 (Top)................................40
1.13 Drum Kit Overhead Microphone Placement Angle 1........................42
1.14 Drum Kit Overhead Microphone Placement Angle 2........................42
115 Hi-Hat Microphone Placement............................................43
116 Tube Tech LCA2A Settings (Channel1)...................................44
117 Tube Tech LCA2A Settings (Channel 2)..................................44
1.18 Ssmart Research C2 Settings...........................................44
119 Empirical Labs EL8X Distressor Settings...............................45
120 Empirical Labs EL8X Distressor Settings...............................45
1.21 Urei 1176 LN Settings.................................................46
1.22 Urei 1176 LN Settings.................................................46
IX


1.23 GML 8200 EQ Settings Left Channel Angle 1(Kick, In).......................47
1.24 GML 8200 EQ Settings Left Channel Angle 2 (Kick, In)......................47
1.25 GML 8200 EQ Settings Right Channel Angle 1(Snare Top).....................48
1.26 GML 8200 EQ Setting Right Channel Angle 2 (Snare Top).....................48
127 DAW Interfaces............................................................49
I. 28 Otari MTR-90 24-Track Analog Tape Machine...............................49
II. 1 5042 Emulation On Kick Drum (Audix D6)...................................57
11.2 5042 Emulation On Kick Drum (Yamaha Subkick)..............................57
11.3 5042 Emulation On Snare Drum (Audix i5)...................................58
11.4 5042 Emulation On Ssnare Drum (Neumann KM86)..............................58
11.5 5042 Emulation On Floor Tom And Small Rack Tom (Sennheiser 421)...........59
11.6 5042 Emulation On Large Rack Tom (Sennheiser 421).........................59
11.7 5042 Emulation On Hi-Hat And Center Room Microphone (Neumann 147).........60
11.8 5042 Emulation On Left Room Microphone (AKG C414).........................60
11.9 5042 Emulation On Right Room Microphone (AKG C414)........................61
11.10 5042 Emulation On Left Overhead Microphone (Neumann U87).................61
11.11 5042 Emulation On Right Overhead Microphone (Neumann U87)................62
11.12 Slate Digital Virtual Tape Machines Settings.............................63
11.13 Slate Digital Virtual Tape Machines Calibration Settings.................63
x


LIST OF ABBREVIATIONS
A/D Analog to Digital
CD Compact Disc
CPU Central Processing Unit
D/A Digital to Analog
DASH Digital Audio Stationary Head
DAT Digital Audio Tape
DAW Digital Audio Workstation
DB Decibels
DCC Digital Compact Cassette
IPS Inches Per Second
MDM Modular Digital Multi-Track
MTRs Multi-Track Recorders
NOS New Old Stock
nWb/m Nano Webers Per Meter
Op Amp Operational Amplifier
PCM Pulse Code Modulation
Preamp Preamplifier
RND Rupert Neve Designs
VTM Virtual Tape Machine
xi


CHAPTER I
INTRODUCTION
History
Thomas Edison produced the earliest known recordings in 1877. With the help of
John Kmesi, Edison used a tinfoil cylinder phonograph to record the human voice. Early
recording technology would continue to develop, with various innovators experimenting
with different materials for the cylinder phonograph. In 1878 Frank Lambert used a lead
cylinder, which is known as the oldest, surviving playable recording. In 1885, Chichester
Bell and Charles Tainter would invent the Graphophone, a machine that used wax-coated
cylinders with vertical-cut grooves. Emile Berliner improved on the early phonographs,
and in 1887 created the Gramophone, which used a flat, hard mbber disk that contained
lateral-cut grooves on one side. These disks could then be mass-produced using a zinc
master disk. By the 18905s, improved versions of the graphophone and gramophone were
in production, and cylinders and disks were being sold to the public along with jukeboxes
[1]-
Birth of Magnetic Recording
In 1898, Vlademer Poulsen invented the first magnetic recording device. The
device used steel wire, and Poulsen called it the Telegraphone. Dr. Fritz Pfleumer
patented the idea of putting magnetic powders onto paper or film in 1928, and by 1931,
Pfleumer and German based electronics company AEG began building the first magnetic
tape recorders. In 1935, German chemical company BASF along with AEG debuted their
Magnetophon to the public, and in 1936 BASF/AEG would record the first live concert
1


onto magnetic tape. Also at that time, BASF had begun manufacturing plastic-based
magnetic tape. Up until this point, the United States had not developed magnetic
recording outside of wire recorders. In 1944, the 3M Company (Minnesota Mining and
Manufacturing) started to experiment with magnetic tape coating in the United States [1].
Magnetic tape recorders arrived in the United States in 1945; U.S. Signal Corps
Captain John Mullin found magnetophones at Radio Frankfurt in Germany along with
1000-meter reels of BASF tape. Mullin sent two of the magnetophones along with 50
reels of tape to the United States; he worked on improving the electronics after returning
from WWII. Mullin demonstrated the magnetophon to Bing Crosby in 1947; ABC and
Philco began taping the Crosby show with one of the magnetophones, and by 1948 the
first U.S. made Ampex Model 200 magnetic tape machines were in production. By the
19505 srecording studios were using analog tape machinesand musicians such as Elvis
Presley and Bill Haley were releasing rock and roll records [1].
Basic Components of Analog Tape
The analog tape machine transforms an electric input into magnetic energy;
magnetic energy is then stored on the tape as magnetic remnants. For playback, magnetic
energy is converted into an electric signal, which can be amplified for playback [2].
Analog tape formulations changed and improved over the years; 3M Scotch 111 gamma
ferric oxide coated acetate tape was used in the early years of the Bing Crosby show [1].
Modern tape formulations are made up of four layers; the base is made of either polyester
or polyvinyl chloride (PVC). The base layer provides most of the bulk of the tape, and is
a durable material that protects the tape from much of the abuse it receives from being
rnn through the tape machine. The most significant component of the tape is the magnetic
2


oxide bonded to the base layer; these tiny magnetic particles are called domains. When a
reel of tape is unmagnetized, the polarities of the domains are randomly organized across
the surface of the tape. Due to the random magnetization of the domains, when the tape is
passed through the reproduce head, the result is a cancellation of the combined domain
energies. Aside from tape noise due to residual domain energy, no signal is produced at
the tape machines output. When signal is recorded onto the tapethe record head
polarizes the individual domains in positive and negative directions; the domains
combine to create magnetic flux. When the tape is passed through the playback head at
the same speed in which it was recorded, the alternating magnetic output is converted
back into an alternating signal. The other components of the tape include a tape coating
and an anti-static backing [2].
Advantages of Analog Recording
According to Bob KatzA finely-tuned 30 IPS tape recorder is more
accurate, better resolved, has better space, depth, purity of tone and transparency than
many digital systems available today. Katz also believes that tape has a greater
bandwidth than 44.1 kHz or 48 kHz digital audio, requiring the need for high sample rate
sessions. There is also the argument that analog distortion is far more pleasant than
digital distortion. Analog distortion gradually and gently obscures ambience and low-
level materialwhereas digital distortion due to rounding errors in digital filters or other
elements in the digital signal chain can sound considerably unpleasant [2].
According to Hugh Robjohns, there are a number of factors that can lead to an
analog recording sounding warmer than a digital recording. Analog electronics may
add tonal qualities to a recording; transformers and inductors cause harmonic and non-
3


harmonic distortions. These characteristics can be captured somewhat with digital
recording through the use of analog preamplifiers, and tube microphones; Katz refers to
this process as adding a warm and fuzzy band-aid to a recording. When recording with
an analog tape machine, there are additional factors to consider regarding how the sound
is affected.
There are certain mechanical factors caused by the tape machinesuch as wow
and flutter and other speed-stability issues. There are several speed variations caused
by an analog tape machine, which occur at different frequency ranges. These variations
include driftbelow 0.1Hz)wow0.1-10Hz)flutter10-100Hz)and scrape
flutterl-5kHz). While these instabilities were remedied to some extent over the years
they are impossible to completely remove from a tape machine. The Studer A820 two-
track machine, one of the most sought after tape machines even to this day, had a
measurable wow and flutter figure of 0.04 percent when running at 15 IPS. In the digital
realmword clock instability is the equivalent of wow and flutter; in a good digital
system, word clock stability is immeasurable [3]. Wow and flutter affects the recorded
audio by creating subtle side bands and noise modulation around the audio. This
modulation adds a low-level grunge to the audio; although well maintained machines
add less of this grunge it still occurs at some extent. Bounce downs and overdubs can
also multiply this effect, as it is a cumulative effect. According to Hugh Robjohns, wow
and flutter are not possible to replicate in a digital recording, and one of the reasons many
engineers have remained faithful to analog tape recording.
Another artifact created by analog tape recording is a phenomenon called tape
saturation, or tape compression. Tape saturation occurs when the recorded signal peaks
4


above 0 dB VU. The result is a rounding off of the transient, due to the physical
limitation of the tape. As the signal level reaches 0 dB VU, the magnetization of the tape
drops, and compression begins to occur. This is a smooth and gradual process, resulting
in the rounding off of the transients. The result is the creation of odd harmonics in the
distorted signal, mainly the 3rd harmonic. Unlike distortion in the digital realm, this kind
of distortion sounds very musical and some instruments such as rock drumsguitar and
bass can actually benefit from this effect as long as it is not overdone. Each instalment
will require different amounts of tape saturation, and that can be adjusted by how hard the
signal to the tape is driven [28].
Flux is also a factor when dealing with tape saturation; flux is defined asThe
amount of density of magnetic particles on tape per meter (nWb/m) [28]. Flux is
measured in Nano Webers per meter (nWb/m), a higher flux level equates to more level
that can be recorded onto the tape. Modern tape formulations enabled higher recording
levels with minimal tape saturation. When calibrating a tape machine an operating level
must be chosen. In general, the higher the operating level, the further you are away from
the noise floor, but you are also closer to the point of distortion (tape saturation). Ampex
initially created a standard recording levelknown as Ampex 0 or Ampex Operating
Level in 1950. Ampex 0 is equivalent to 185 nWb/mand all early alignment tapes
followed this standard. As tape formulations improved and were more capable of
handling higher levels, Ampex 0 was still referenced. For example, a tape designed to
record levels at 250 nWb/m were known as +3and thus could handle an additional 3
dB of headroom before distorting [28].
5


"Analogue recording tape is inherently 'non-linear5, its effect being determined
by a combination of tape formulationrecord and replay head constructiontape speed
tape width, record and playback equalisations (and phase shifts), and the level and
waveform of high-frequency bias [3]. These factors introduce harmonic distortions (at
low frequencies), frequency and phase irregularities and more importantly, reduce
dynamic range. Self-erasure and magnetic saturation mainly affect high-frequency
transients. In order to avoid low and mid-frequency harmonic distortions, tape machines
can be over biased; the trade off being at the expense of high-frequency extension and
transient accuracy. While it could be argued that this is a negative effect of analog tape
recording, this imperfect characteristic of analog tape recording is said to sound more
natural than a near-perfect digital recording [3].
Disadvantages of Analog Recording
Katz neatly summarizes the biggest disadvantage of analog recordinganalog
requires constant vigilance to sound good [5]. Analog tape machines require consistent
maintenance, including biasing, calibration, and cleaning to function to their fullest
extent. Another important consideration is cost; some important factors to consider are
the price of the machine, parts and labor, transportation or shipping costs, as well as the
cost of tape. There are currently no new analog tape machines being manufactured, which
means the market consists of used machines that range in condition. Some manufacturers
such as Otari have remained in business and continue to produce parts for their machines,
while other 3rd party companies have begun to produce replacement parts for a number of
the more popular tape machines. Tape manufacturers have also become more rare, though
there are currently a handful that are producing new reels. RMG International,a company


based out of the Netherlands, and ATR Magnetics from York, Pennsylvania are two of
the remaining tape manufacturers. New Old Stock (NOS) tape can also be purchased,
which is essentially old, unused tape from the heyday of analog tape recording. Used
reels can also be purchased at a discount, but it is generally unwise to re-use a reel more
than three times.
Flexibility is another issue when working with analog tape recorders. Analog
editing is possible, through the use of a razor blade and splicing tape. While this type of
editing is more time consuming and perhaps less precise than digital editingit isnt
impossible, and splicing was once a necessary skill for audio engineers. Another issue
with analog tape recording is track count. In a good digital audio system, track count is
rarely an issue, and most systems provide a nearly unlimited number of tracks. With
analog recording, the track count is based on the machine and reel of tape. Professional
multi-track tape recorders were generally produced in 8,16, or 24-track configurations
using either one or two inch tape. In the earlier days of analog tape, 4-track machines
were the standard. When the Beatles recorded many of their classic albums, only two-
track and four-track machines were available. To work around this limitation they used a
process called submixing. If a four-track reel was full, they would submix these existing
tracks to one or two tracks on a new four-track machine. While this method workedit
meant several instruments had to be summed together onto a single mono trackand EQ
levels and effects were recorded directly to tapeand thus couldnt be undone [8]. This
process was used even when 24-track tape machines were the standard for commercial
recording studios; often times two 24-track tape machines would be used for recording
and bouncing down. The Smashing Pumpkins and producer Butch Vig used two 24-track
7


Studer tape machines to record the album Siamese Dream in 1992. Some songs had as
many as 40 guitar parts, so bouncing down to a second machine was essential in the
production of this album [9].
Digital Recording
While the ability to record using a digital device was not developed until many
years later, Alec H. Reeves invented pulse-code modulation (PCM) in 1937 while
working for the International Telephone and Telegraph Co. in France. Bell Labs and
other telecommunication companies used PCM sporadically over the years; it wasnt
until 1972 that the Nippon Columbia Co. invented a PCM recorder This recorder was
used to master soundtracks, and audio was stored on videotape, which roughly contained
87 dB of dynamic range. Around this time period, others were experimenting with digital
audio. In 1962 Tom Stockham of MIT was creating digital audio tape recordings using a
TX-0 computer and analog to digital (A/D), digital to analog (D/A) converter created by
Bernie Gordon of EPSCO. In 1975, Stockham and Malcolm Lee founded Soundstream
and created a 16-bit digital audio recorder While digital audio was being experimented
withit wasnt a practical method of recording until Sony/Phillips introduced the Digital
Audio Tape (DAT) in 1986. DAT recorders use a tape smaller than a standard cassette
tape, and offered the ability to record at sampling frequencies of 32, 44.1 and 48 kHz [2].
Stationary-Head Transport Versus Rotary Head Transport. Stationary head
recorders used technology similar to analog tape recorders. One of the reasons for their
popularity was that they were cheap to produce. The downside was they offered low
head-to-tape speed, which either meant a low data transfer rate, a very high density of
data on the tape, or both situations occurring. Rotary-head machines essentially had the
8


opposite characteristics; high head-to-tape speeds, high data transfer rates, and lower data
density on tape. Lower data density on the tape reduced the demands on the tape itself. In
the early days of digital recording, manufacturers had enough issues creating accurate
A/D and D/A converters, and thus chose to use existing video recorder technology (rotary
head transport), rather than reinvent the transport head. Although the majority of CD
mastering recorders used video transports to store digital audio, Sony, Studer, Mitsubishi
and Philips created stationary-head digital recorders [7].
Digital Audio Stationary Head, Pro-Digi, and Digital Compact Cassette. Stationary-
head recorders became the dominant 24 and 48-track digital recorders in the early years
of digital recording. Mitsubishi invented Pro-Digi (PD)and offered machines in 2,16
and 32-track formats using quarter-inch, half-inch, and 1-inch tape. Although the PD
machines were popular for some timeMitsubishi stopped production as Sonys Digital
Audio Stationary Head (DASH) format gained popularity in the stationary head market.
DASH recorders were available in 2, 24 and 48-track versions, with the first models
appearing in 1987. DASH recorders were eventually capable of recording at 24-bit.
Philips invented the Digital Compact Cassette (DCC) as a means to replace the analog
compact cassette. DCC was invented around the same time as DAT; the two formats
were referred to as R-DAT and S-D AT (Rotary head and Stationary head). DCC was
more of a consumer hi-fi format but never gained too much popularity due to the
popularity of CDs and Mini discs [7].
AD AT Recorders. The next advance in digital recording was the creation of the AD AT
recorder, which was invented by the Alesis Corporation in 1991. Each AD AT machine
could record 8 tracks to a S-VHS videocassette, and up to 16 AD AT machines could be
9


connected together enabling the user to record a total of 128 tracks. In 1992, Tascam
released the DA-88, the first modular digital multi-track (MDM), which used Hi-8
videotape [1].According io Modern Recording Techniques, MDM recorders were
responsible for the switch from analog recording to digital recording in professional
recording studios. Over the years other digital recording technologies were invented
including AD AT MDM recorders, the Digital Tape Recording System, as well as hard-
disk recorders and MiniDisc recorders [2]. With the exception of hard-disk recording
units, most of the early digital audio recorders have been taken out of production, mostly
in favor of the Digital Audio Workstation (DAW).
The Digital Audio Workstation. A DAW is a computer based hard-disk recording
system, usually integrated with an audio interface that acts as an A/D, D/A. Some
interfaces also include microphone preamplifiers, MIDI interconnectivity, monitor and
headphone controls, as well as other features. DAW software allows the user to record,
edit and mixas well as sequence MIDIand use virtual instruments. DAW software also
allows the user to affect the audio with plug-ins. Plug-ins often act to replicate
processes done in the analog world such as equalization, compression, and many other
effects. Popular DAW software includes Avids Pro ToolsApples Logic Pro
Steinbergs Cubaseas well as many other programs that all feature their own unique
benefits.
Basic Components of Digital Audio
The two basic components of sound are frequency (component of time) and
amplitude (signal level); in digital audio these two components are sampling (component
of time) and quantization (signal level). Unlike analog recording, digital recording does
10


not occur in a continuous manner; instead it uses a process where it takes periodical
samples of an audio waveform. These sampled signal levels are transformed into a
representative stream of binary words that can be stored and later manipulated.
Sampling. With a digital recording system, the user chooses a sample rate, which is the
number of samples of analog signal taken in one second. Sample rate determines
bandwidth; therefore a higher sample rate can store more frequencies at its upper limit.
The reciprocal of sample rate is sample time, or the elapsed time between each sampling
period. A commonly used sample rate of 48 kHz would correlate to a sample time of
1/48,000th of a second. The sample rate determines what timed intervals the analog signal
is sampled at. The analog signal is held at each interval, during this temporary hold the
A/D converter determines what the voltage level of the signal is. The accuracy of this
process is dependent on the circuitry used in the converter and the bit rate.
The Nyquist Theorem. Dr. Nyquist discovered his sampling theorem while working for
Bell Labs, and it has become one of the fundamental building blocks of digital
technology. The theory states that, uA sampled waveform contains ALL the information
without any distortions, when the sampling rate exceeds twice the highest frequency
contained by the sampled waveform [24]. For examplean audio signal with a
bandwidth of 20 kHz would call for a sample rate of 40 kHz samples/second.
Additionally, no signal great than half the sampling frequency may enter into the digital
conversion process. If frequencies greater than one-half the sample rate are allowed to
enter the signal path, false frequencies could become audible. These false frequencies are
referred to as alias frequencies, and can be heard as harmonic distortion.
11


Quantization. The other component of digital sampling represents amplitude (signal
level). In order to store and manipulate digital audio, quantization is used to transform
voltage levels of continuous analog signals. Voltage levels are transformed into binary
digits (bits). It is the job of the converter to determine the correct voltage level of the
analog signal, and output a set of analogous binary numbers. The binary numbers
represent the originally sampled voltage, and are grouped together as a word. The
converter does this process during a sample interval, at which point the voltage level is
momentarily held. The accuracy of this process is dependent on the words bit lengthand
the design of the system. Common binary word lengths for professional digital recording
systems include 16-bit and 24-bit, although some systems can perform calculations at 32
and 64 bit resolution. Greater internal bit resolution corresponds to higher quality. This is
due to the fact that errors mostly occur within the least-significant bits. The least-
significant bits are the final and smallest numeric value in a digital word. Higher
resolution produces a data stream nearly free from errors.
Advantages of Digital Recording
Digital recording has many advantages that differ from those achieved from
analog recording. According to Stockhama digital recording is robust if a recording
contains a billion bits, and none are changed when the recording is played back, then the
recording is exactly the same. While this may seem like a fairly simple concept, the same
is not true for an analog recording; a reel of analog tape can decay over timeor the
machine itself may be responsible for variations in the playback of the tape [4].
Another advantage to digital recording is high dynamic range; recording with a
16-digit system, it is possible to achieve dynamic ranges of 90 dB or higher
12


Additionally, digital recording produces negligible modulation noise, modulation noise is
often 4 or 5 dB or less. According to Stockham, digital recording produces very low
levels of distortion; both conventional distortions and those due to digitization are very
small, even when reaching maximum signal levels [4].
Digital recording is known for having a flat frequency response at all levels.
There is no low-frequency cutoff due to any digital processes. Additionally, full power
bandwidth is possible with digital recording, in the words of Stockham; high frequency
headroom is not an issue [4].
A common issue with analog recording is an effect known as print-through;
print-through is due to storing tape for long periods of time, and essentially causes audio
to be transferred from one layer of tape to the other. This effect is not possible with
digital recordingwhich reinforces Stockhams statement that digital recording is
robust. Similar to print-through is an effect called crosstalk which is an effect where
simultaneous channels bleed into each otherusually occurring in low frequency
ranges. Because of this effectsimilar instruments had to be grouped together on the tape.
For examplea kick drum would occupy track 8, and a bass guitar would occupy track 9.
With digital recording, crosstalk can only be generated by analog electronics. Another
common concern with analog recording is self-erasure of audio at high frequencies at
high levels; this phenomenon cannot occur with digital recording [4].
Disadvantages of Digital Recording
According to Bob Katz, there is both good and bad digital equipment; bad digital
equipment can sound edgy dimensionless hard-sounding and even unclear
whereas good digital technology aims to be transparent. Bad digital equipment produces
13


distortions that increase edginessand hardnessin a recording. These unwanted
effects could be due to a number of components in the digital signal chain including poor
converters, sharp filters, low resolution, jitter, improper dither, and other factors that
occur in the analog signal path. Katz warns that placing A/D and D/A converters inside
one chassis can cause major problems, add in the other components needed such as
motors and spinning heads, and there is potential along the signal path for digital
distortions and other errors. While digital technology offers a cheap recording solution to
many, some of these low-end equipment manufactures are producing equipment that Katz
would refer to as bad digital. Katz concedes that digital technology has come a long
way from the early multitrack recorders (MTRs)but that even now an acceptable to
very good MTR is in the price range of $2000. Other factors that have increased the
sound quality of digital recordings are higher sample rates and bit depths offered on even
the most basic MTRs [5].
Most engineers are aware of the common problems associated with digital
recordingand the supposed harshness it adds to a recording. A common solution is
using more analog equipment in the signal chain. There has been a resurgence of analog
equipment including tube microphones, tube preamplifiers and outboard equipment such
as compressors and equalizers. Analog equipment is often used to add warmth to a
recording that would be otherwise impossible to gain from a purely digital recording.
Katz warns that this is more of a band-aid than a cure, but these processes can create a
sort of fuzzy blanket that covers up the unwanted edginess produced by a digital
system. While digital recording has improved tremendously in sound quality, bad digital
recording is due to two main factors; linear frequency response, which often reveals non-
14


linearities in other parts of the signal chain, and built-in distortions in the A/D or D/A
conversions [5].
The Analog and Digital Hybrid Studio
In the early days of digital recording, issues such as poor word clocks, or bad A/D
and D/A conversion kept many studios from making the jump from analog to digital.
Many of these disadvantages have been overcome with better technology, which in turn
has also made digital audio more affordable for the commercial recording studio and
home studio engineer Digital audio has certainly become more practical, whereas analog
remains revered for its character A hybrid studio is defined as a studio in which a DAW
is the central component, where analog hardware and digital software interact together
[12]. Commercial studios have operated in this fashion for many years. Atypical set up
would involve a DAW and a computer Additionally the DAW would need A/D and D/A
converters and a word clock. Most commercial facilities are centered around a large
format analog console, which contain microphone preamplifiers, equalizers, and
sometimes other processors such as compressors/limiters. Racks of outboard analog
equipment often times occupy studios. This equipment alongside the DAW gives the
engineer the best of both worlds, analog fidelity and digital efficiency. This can be taken
one step further, by integrating a tape machine into the signal chain. Eight,16 or 24 track
tape machines can be used for basic tracking of one or all instalments in a recording
session. These tracks can then be recorded into a DAW, and further processed, edited, or
added to with overdub recordings. The possibilities here are endless, as the engineer can
mix completely in the box using the DAW and plug-in processesor outside the box
using analog hardware. Another common technique is to use a combination of the two to
15


achieve the finest possible results. Lastly, the engineer can bounce down using a two-
track tape machine before mastering to further provide character to the recording.
Analog Integration in the Project or Home Studio
Modular Systems. With the rise of modular audio processing racks, project and home
studios are able to easier incorporate analog equipment into their often times smaller
studio spaces. This means the budget and space conscious home studio owner can use
much of the same professional quality analog equipment used in larger, professional
facilities. Modular and standalone audio equipment has gained a tremendous amount of
popularity. An article discussing New Products for 1988 in an October 1987 issue of a
popular trade magazine listed only three standalone microphone preamps. Today
countless manufacturers produce standalone and mutli-channel preamps and other
outboard equipment. Additionally, various modular systems have gained popularity, most
notably the API 500 series and their Lunch Box rackas well as the Solid State Logic
X-Rack and Tonelux V-Rack. Modular systems are compact, enabling them to be used in
the studio, or transported outside the studio for on location recording sessions. Another
convenient feature of modular systems is that they feature all the input/output routing on
the rear of the chassis, and only require one power supply for the entire rack. Modular
systems are sometimes referred to as analog building blocks, enabling the engineer to
create their own lego studio. Another benefit of modular systems is they allow the
engineer to build slowly, without having to pay all of the cost up front. An engineer can
simply buy a microphone preamplifier, and chassis, and later add more preamplifiers, or
an equalizer and compressor to build a channel strip. This alleviates some of the upfront
cost that is required when buying a large format analog console.
16


The Tonelux V-Rack comes in two models, a 16 slot or 8 slot chassis. Modules
can be placed in any order the user sees fit. Current modules include a microphone
preamp, an equalizer, a compressor, and a plethora of other unique modules including
stereo and surround mixing and aux modules, master output modules, monitor modules
and even faders. The flexibility of this modular system allows a user to create channel
strips, a summing amp, and even a fully functional stereo or surround console. Perhaps
the only downside to the Tonelux V-Rack is that modules and the chassis are currently
only compatible with each other, and there are no third party manufacturers producing
modules for this format [15].
Perhaps the most complex of the modular systems is the Solid State Logic (SSL)
X-Rack. The X-Rack chassis can accommodate up to eight SSL modules. The available
modules include several microphone preamplifiers and compressors, an equalizer, an
eight input summing module, and a master bus module. The X-Rack can be configured as
several SSL channel strips, a summing amp, or a collection of audio processing tools.
What makes the X-Rack unique from the other modular systems is their Total Recall
feature, which enables the rack to recall exact settings on the modules. Each X-Rack
features a microprocessor for the Total Recall system to function, as well as the ability to
store 32 recall settings. Total Recall settings can also be exported or imported through the
MIDI interface on the back panel of the chassis. Additionally, three X-Racks can be
connected to the Total Recall system of any SSL AWS900-series analog console using
nine-pin d-sub connectors. A unique feature of the Total Recall system is the ability to
copy settings from one module to another of the same type, this feature is highly useful
for modules acting as a stereo pair. The SSL X-Rack is essentially modeled to act and
17


sound like a miniature SSL console. This modular setup is ideal for an engineer without
the ability to own a large format analog console, but looking to add classic SSL character
into their recording or mixing chain. Much like the Tonelux system, SSL X-Racks and
modules are only compatible with each other [14].
The 500 series was originally developed and used strictly by API; this format
provided several modular units including a preamplifier, equalizers and compressors. API
also produces a Lunch Box chassiswhich can house and power up to six modulesas
well as a ten-slot chassis. Since 2007, third part manufacturers have begun making
modules and racks for the 500 series. API has since created the VPR Alliance, a
standardized program for third party manufacturers to conform to when developing
modules for the 500 series. The guidelines provide design specifications that ensure
modules physically fit into the rack, as well as conform to the electronic standards of the
API racks. The VPR Alliance also ensures each module is receiving the correct amount
of power therefore no modules are underpowered. The 500 series is by far the most
popular modular system on the market, with many third party manufacturers producing
both racks and modules. Racks are being manufactured that can contain one or two
modules, with larger racks holding as many as ten. Aside from having the option to use
third party manufacturers modules, the 500 series is compact and portable. The API ten-
slot chassis only uses three rack mount spaces, can hold up to ten modules, and needs
only one power supply. Using other stand-alone rack equipment would require at least 16
rack spaces, as well as multiple power supplies or IEC power cables. The startup cost of a
rack and two preamplifiers is around the same price as a standalone two-channel
preamplifierbut in the long run buying more modules to fill the rack would most likely
18


end up being cheaper than buying another standalone preamplifier or other effects
processor Innovations are even being made in the world of 500 series equipment;
recently Aphex released a four-slot 500 series rack that also doubles as a USB interface
for a DAW. This chassis can house up to four modules, and features an additional S/PDIF
input/output for two more channels of audio. Other features include studio monitor
outputs, headphone outputs and MIDI connectivity. This piece of equipment tmly shows
the direction the analog/digital hybrid studio is headed in [16].
Analog Integration in the Recording Process
Perhaps the most straightforward method of incorporating analog character into a
recording is during the tracking process. Even when working with a DAW, it is fairly
simple to integrate analog devices into the signal chain. In the digital signal chain, the
two most important components are the A/D, D/A converters and the word clock. The
two most important pieces in the signal chain before reaching the A/D converter are the
microphone, and the microphone preamplifier. There has been some rise in popularity
towards straight wire with gain preamplifiers; these cleanor neutralsounding
preamplifiers are suitable for many types of instruments. Still thoughthere are plenty of
options for preamplifiers that will give the source material a more colored sound.
Although the technology has been in use since the early 19005s, vacuum tube equipment
has remained popular and even sought after in professional recording studios [17]. Tube
microphones, preamplifiers, equalizers and compressors are all valuable equipment that
can be integrated into the project studio. Tube electronics add a small amount of second-
harmonic distortion, which our ears often find delightful[22].
19


Engineers also often talk about equipment with transformers. Transformers have
played a crucial part in circuit design since the earliest days of analog audio equipment.
Its fairly common to see transformers at the inputoutput and amplification stages of
analog equipment. Harmonic distortion occurs in transformers due to hysteresis (low-
level signals) and saturation (high-level signals) [3]. Low frequencies are usually affected
greater than mid to high frequencies. Hysteresis can cause quieter signals to sound
richer and denser due to the added harmonics. Because transformer based equipment
has a slightly higher distortion ratio than transformerless equipment, it tends to produce a
more colored sound [3]. Good quality transformers are expensive, which is one reason
manufacturers have gone transformerless. Another reason for the decrease in transformer-
based preamps is they are not as necessary when working with solid-state equipment. An
input transformer is used to match the low output impedance of a microphone to the high
input impedance of a vacuum tube [22]. Output transformers provide a balanced output
that will work well with any input, balanced or unbalanced. Exceptional sounding
preamps exist that are both transformer based and transformerless. Although not always
the case, transformer based preamps will add more coloration to the sound source.
Another factor to consider is whether or not the microphone uses a transformer
A component often discussed in analog audio equipment is the operational
amplifier (op amp). An op amp is a type of amplifier that performs a mathematical
operation. In a microphone preamp, it is responsible for multiplying the input voltage by
the desired gain [22]. Vacuum tube op amps were created by Bell Labs and used
frequently in the 1940s and through WWII. In the 1950s and 60s solid-state op amps
became a suitable replacement for tube op amps; tube op amps were bulky and consumed
20


large amounts of power [23]. Integrated circuit (IC) op amps were developed in the mid
19605s and continue to be improved on [18, 23]. Up until about 1977, most solid-state
amplifiers used discrete transistor Class A circuitry. 1977 saw the introduction of the
TL072 and 5532 op amps, which we suitable for use in solid-state preamplifiers, and still
remain popular choices in audio equipment. Some popular op amps used in microphone
preamplifiers include the Jensen 990, the API 2520 and the Burr Brown PGA2500.
Variations and clones of these op amps are often used in many beloved preamplifiers, and
the Burr Brown PGA2500 has become popular in many DAW preamps as it offers
digitally controlled gain [22].
The combination of quality microphones and quality microphone preamplifiers, as
well as a good digital signal chain can lead to an exceptional recording. Additionally,
many engineers will incorporate analog equalizers and compressors into their recording
signal chain. With a large format analog console, this can be done through the use of
insert sends and returns. Many smaller project studios can make use of outboard
equipment through the use of a patch bay. These processes are normally done somewhat
subtlety; a common example would be an engineer using an EQ to get rid of the ringing
sound in a snare drumor using a compressor to even out the dynamic playing of a
bassist. Of course these processes can also be done more extreme, often times an engineer
will use a compressor on a drum room microphone to literally squash the dynamics.
Other times, the engineer may choose not to use any additional processing, and they can
certainly later add more analog character in the mixing and mastering phases.
Analog tape can be taken advantage of in the tracking process, by either recording
one instalment or all instalments to tape. A common use of analog tape in the modern
21


hybrid studio is to track dmms onto tape, and then record the output of the tape machine
into the DAW. This gives the engineer the flexibility of digital, and the sound of analog.
Additionallyother instruments can later be overdubbed into the DAW. Drums are
commonly given this treatment as analog tape is known to give dmms a desired low
frequency boost, and can tame cymbals, making them sound more natural. Still though,
some engineers rely on tape for the entire recording session, choosing to then record their
analog tracks into their DAW of choice for mixing and editing. While to some this may
seem like an extra step in the recording process, it gives the engineer the best of both
worlds. Analog tape can also be used when bouncing down a mix for mastering. An
engineer can sum their mix using either analog or digital means, and record this stereo
mix onto either a or two-track tape. This tape can then be sent to the mastering
engineer. This is a quick, and cost effective way to impart analog character into a mix.
Modern Examples of Analog Recording
One of the more popular musicians advocating for analog use in recording is
Dave Grohl and his band the Foo Fighters. Their 2011 album Wasting Light was recorded
strictly with analog tape. Although the Foo Fighters own a professional recording studio
in Los Angeles, CA, Grohl chose to record the album at his home in Encino, CA. Grohl
essentially brought in enough equipment to turn his garage and spare room located above
the garage into a recording studio. This included two Studer A827 tape machines, an API
1608 analog desk, and a surplus of outboard analog equipment. Throughout the process
Grohl insisted on not having a computer in the converted recording studio. Grohl and the
Foo Fighters enlisted the help of producer Butch Vig (Nirvana, Smashing Pumpkins) and
engineer James R Brown (Nine Inch Nails, The Killers) to record the album. Minimal
22


acoustic treatment was done in the garage where the drums were recorded to achieve a
sort of unpolished and raw sound. It took roughly 13 weeks to record the album, and then
Alan Moulder was brought in to mix the album. Mixing originally started at Chalice
Studios in HollywoodCAbut the majority of the mix was completed at Grohls
converted home studio. All the mixing was done from the analog tapes, and the only
instance of digital equipment entering the signal chain was through the use of an Eventide
digital reverb, Lexicon PCM42 delays and an Eventide Eclipse used for vocal doubling.
Wasting Light was very well received upon its release, including winning a Grammy for
Best Rock Album. Vig was quoted as saying, "people say it sounds honest, unlike
anything theyve heard lately [27].
Another highly successful album recorded with analog tape is Tools 2006 album
10,000 Days. The album was recorded and mixed by Joe Barresi (Queens of the Stone
Age, the Melvins) using Studer A827 tape machines and Ampex GP9 tape. The album
was recorded into Pro Tools strictly to archive the recordings [6]. In 2005, Andrew
Scheps engineered Stadium Arcadium, the ninth full-length album by the Red Hot Chili
Peppers. A unique aspect of this album is the vinyl release; the album was recorded to
two-inch analog tape, mixed on an analog console to half-inch tape, and mastered in
analog. Lastly, the album was cut to vinyl, keeping the entire signal chain analog [26].
While these are just a few examples of successful albums recorded using analog tape
there are still plenty of other musicians and engineers using analog tape. Jack Shirley,
who owns and operates the Atomic Garden, a studio based out of Palo Alto, CA uses an
analog/digital hybrid approach for recording and mixing. Recording is done with a 2-inch
tape machine, and then transferred into a DAW for editing, archiving and to take
23


advantage of some of the other benefits a DAW offers such as automation. Mixing is also
done in the analog domain, using an analog mixer and other hardware, and half-inch tape
[10].
Quite possibly the most famous advocate of analog tape is Chicago based
engineer Steve Aloim. Albini has worked on over 2000 records, and is most famous for
his work with Nirvana, the Pixies, Robert Plant and Jimmy Page. Albim has owned and
operated Electrical Audio since 1997, a multi-room recording studio that features
multiple analog tape machines and very few pieces of digital equipment. I have always
done things with the analogue method, and I still think it's the best method. So I have no
reason to change. I've had a long time to accumulate equipment and microphones and
techniques, and I've never been in a situation where I've had to say 'No, I can't do that,
because we're working on tape.' If there were problems that I could not solve on tape, I
might be compelled to use computersbut I've never encountered such a problem [25].
Additionally, Albini feels that high-resolution digital audio such as Direct Stream Digital
(DSD) and the Super Audio CD (SACD) souncTok but still not as good as a well made
vinyl record [25]. Albini refuses to sacrifice quality for convenience; and while Albini is
somewhat of a rare breed, his dedication to analog tape proves that not all engineers are
sold on the quality of digital recording.
Analog Integration in the Mixing and Mastering Process
Analog equipment can easily be integrated into the mixing and mastering
processes, even if the engineer plans to mix mostly in their DAW. For a project studio
looking to add analog character in their mixes, an interface with plenty of analog outputs
24


and inputs is essential.A patch bay can also be used to give the engineer more flexibility
with their routing options.
Analog equalizers, compressors, limiters and other outboard effects come in
many different varieties; tube, solid state, mono, stereo, etc. For a project studio with a
more limited budgetits important to consider the price of equipmentbut also how
versatile the equipment is. A few factors to consider are will this piece of equipment
work well with multiple genres of music? Is this piece of equipment best suited for only
certain instrumentsor will I be able to use it on many instruments? Is this piece of
equipment mono, and if so, will I need a stereo pair?
Professional mastering studios rely heavily on analog equipment for their signal
processing. While the majority of audio is sent to the mastering engineer as a digital
audio file, the mastering engineer will generally use a combination of analog equalizers,
compressors, limiters and other highly specialized equipment. A mastering engineer
generally performs the duty of mastering as their equipment is more suited for the task,
and their studios are often acoustically treated in a different manner than that of a
recording studio.
Analog Summing Versus Digital Summing. In the days of analog tape, and even early
on in the existence of digital recordinga mixed album or track was summed on a large
format analog console. The channel signals were essentially mixed together at the group
or main stereo busses. While some still work in this fashion, as digital technology has
improved and become extremely popular and convenient, most summing is now done in
the digital realm. With digital summingmixing occurs in the DAWor in the box with
the final mix being bounced down or printed to a single mono, stereo or multi-channel
25


audio file. A fixed-length sample is created to represent the mixed tracks. For early
digital recording systems and consoles, this task sometimes proved to be too much due to
rounding errors and other complications. Large track counts correspond to a large number
of signal samples being added together, which creates complex binary numbers. As
digital technology improved, the issues associated with digital summing disappeared.
Although there are problems associated with analog summingsome engineers still prefer
it to digital summing. Perhaps these engineers enjoy being able to physically touch faders
or knobs as opposed to mixing in a DAW. Most problems associated with analog
summing are due to inferior analog hardware that simply doesnt have the necessary
headroom. While it makes sense for a home studio to sum in the digital domain,
manufacturers have begun producing analog summing boxes with the space conscious
engineer in mind. Manufacturers such as Dangerous, Rupert Neve and Tonelux have
popularized analog summing boxes which often consume as little as one to two rack
spaces. These summing boxes allow the engineer to send their outputs from their DAW
into the summing box, mix their signals with physical knobs or faders, and then send the
stereo signal back into their DAW or to a two-track tape machine. While these units take
up less space than a large format analog console, the number of inputs, usually either
eight or 16, often limits them. Limited inputs means the engineer usually needs to premix
some of their tracks in their DAW, or buy and link together multiple summing boxes.
While there are advantages and disadvantages to analog summingits often overplayed
that it will make a mix sound better In reality neither method will make or break a mix.
There are plenty of world famous engineers who use digitally summing, such as Dave
26


Pensado, Charles Dye, and many others; likewise, there are plenty of engineers who still
prefer analog summing.
Mixing In The Box Versus Out Of The Box. Possibly the greatest advantage to mixing
in a DAW is being able to recall settings. This gives an engineer the ability to save a
session, come back to it at a later date, and pick up right where they left off. It also gives
the engineer the ability to work on the session at nearly any studio, assuming of course
they have compatible software. While the quality of digital plug-ins has improved
tremendously, mixing with a DAW also gives the engineer the ability to use automation.
Control surfaces have become quite popular with the rise of digital audio. A control
surface gives the engineer the ability to automate mix settings such as volume levels,
panning, mutes, and even plug-in settings. Some manufacturers have popularized hybrid
consoles, which feature analog processing such as preamplifiers and equalizers, but also
offer the ability to act as a control surface for a DAW. Perhaps one of the most exciting
elements of mixing in a DAW is the nearly unlimited options the engineer has when it
comes to plug-ins. Although the quality of plug-ins can vary, even some of the most
renowned plug-ins are often times cheaper than their analog counterparts. Mixing in the
box also doesnt require a patch bay or patch cablesor the need for a large format analog
console. The need for an interface with plenty of digital to analog conversion is also
unnecessary if the engineer plans to mix solely in the box, and it5s possible to mix with a
simple USB or Firewire interface.
One factor that must be considered when looking to mix in the box is computer
specifications. Higher track counts and more instances of plug-ins require a computer
with plenty of RAM, and powerful CPU5s. Typically, a computer with stock
27


specifications will not cut it for an engineer planning to do a lot of recording or mixing in
the box. While advances in technology such as CPU hyper-threading are making this less
of an issue, the specifications of a computer should be carefully considered by an
engineer planning to mix or record in the box.
According to Andrew Scheps (U2, Michael Jackson, Iggy Pop) "Many of the
same mistakes can be made in analogue and in digitalthe only difference is that theyre
more easily made in the digital domain [26]. Scheps uses a hybrid approach to mixing
that is quite practical. Scheps starts mixing by using Pro Tools for a number of mixing
taskswhich he considers structural moves these tasksinclude submixing instruments.
For exampleall the drum tracks will be combined to occupy roughly 10 faders on his
analog mixing desk. Scheps considers this prep work an essential step in his mixing
process. After he has all the tracks laid out across his two Neve 8086 analog desks, he
begins moving faders and inserting analog hardware. For Scheps, the main reason for
working in the analog domain is being able to physically touch knobs and faders, instead
of hunting around for something on a computer screen. Because Scheps mostly works out
of his personal studio, his workflow is very similar from project to project, enabling him
to quickly make adjustments. His Neve desks also feature flying faderswhich allows
him to use automation. While Scheps has an entire wall of analog hardware, he does use
the occasional plug-in. Scheps feels that digital recording is more forgiving whereas,
"Analogue colours the hell out of the sound, and this can be an amazing thing, but you
have to know what youre doing. You have to be aware of the gain structurethe noise
floorall these things that you dont really have to worry about the same way with
28


digital. Not only does this method of mixing offer a more hands on approachit gives a
unique sound that is harder to replicate in the digital domain [26].
While some analog hardware aims to be completely transparent, other pieces of
equipment are said to sound warmer, punchier, and fuller due to harmonic distortion
provided by the circuit path. The downside to using analog equipment is the extensive
documentation required to recall settings at a later date. Analog equipment also requires
an interface capable of outputting multiple channels of analog audio, as well as other
signal flow considerations. For the project studio owner, most choose to work in the
digital domain, but it is fairly easy to incorporate a few pieces of analog equipment into
the signal chain. A project studio owner should choose equipment that suits their mixing
needs, as there are plenty of affordable options to choose from.
29


CHAPTER II
METHODS
Purpose of the Study
This study was conducted to determine if analog tape plug-in or hardware
emulation could accurately mimic a tme analog tape recording. Further, this study was
conducted to determine what elements can and cannot be emulated by analog tape plug-
ins or hardware emulation.
Overview
To conduct this studyan acoustic drum kit was recorded simultaneously to
analog tape and a DAW (Pro Tools HD). The Euphonix CS200OP console allows options
to split an audio signal through the use of its busses. Upon amplifying the microphone
inputs with their perspective preamplifiers, the signals were then split into the MTR-90
and A/D converter. This allowed for a completely separate analog and digital recording
of the same performance.
Drums were recorded onto analog tape due to the nature of the instrument; drums
are more transient than the other instalments involved in this recording. The style of
music for this project is rock.
Analog Tape/Pro Tools Specifications
All audio recorded in Pro Tools was recorded at 24 bit, 96 kHz. Dan Lavry of
Lavry Engineering Inc. argues there is an optimal sample rate, and recording above the
optimal sample rate compromises the accuracy of audio. Lavry believes it is good
practice to record the signals that are needed, while keeping everything else out (energy
30


outside the human range of hearing). Lavry concedes we should accommodate the most
sensitive earsand allow a safety margin of 10 kHz. According to this theorythe
optimal sample rates are 88.2 or 96 kHz. Ultrasonic frequencies describe sound waves
with a frequency above the upper limit of human hearing [13]. Capturing ultrasonic
frequencies can potentially cause unwanted audible alterations due to non-linearity in
equipment. Non-linearity causes a distortion called intermodulation, which is rather
unpleasant to the human ear as a result of this distortion being non-harmonic. Harmonic
distortion tends to alters the timbre, it 'colors the sound5 by changing the relative
harmonic content [13]. Intermodulation is much more offensive to the human earas it is
not related to the sound or its harmonics.
Linearity is worse in the ultrasonic frequency range, and therefore better in the
audible range (lower frequency ranges). The simple solution is to avoid recording
ultrasonic frequencies because the spill over could cause unwanted intermodulation.
Another reason to avoid sample rates higher than 88.2 or 96 kHz is that most
microphones are designed to mimic the human hearing range; therefore recording above
the frequency range of a microphone will not positively affect a recording. According to
Lavry, at best ultrasonic frequencies will cause no harm to a recording, but they will also
not help a recording in any way. A recording at 96 kHz has a theoretical bandwidth of 48
kHz, while the converters available today give a bandwidth of approximately 40 kHz.
2 ATR Magnetics Master Tape was used for this recording. ATR Magnetics is
currently the only analog tape manufacturer in the United States, and their tape is known
for low noise, high output and high resolution [11].A speed of 30 IPS was used for this
recordingwhile both 15 IPS and 30 IPS are considered professional speeds; each has
31


their own distinct advantages. Many claim that 15 IPS has a better bass response, and
there are also claims that 30 IPS has a better high-frequency response and a flatter overall
frequency response. Its also believed that 15 IPS produces more noise than 30 IPSbut
that can also depend on the machine, and how many tracks are being recorded (16 tracks
vs. 24 tracks). The Otari MTR-90 was calibrated at +9 for this recording.
Tracking Procedures
Basic tracking was conducted over the course of two days, July 15th and 16th 2013
at Colorado Sound Studio. The dmmset was placed in the larger of the two live rooms.
The dmmmer did not play to a click track, and instead we opted to set up a headphone
mix where the other musicians could play along with the dmmmer and provide scratch
tracks.
Two dynamic microphones were used on the kick drum; an Audix D6 was placed
roughly six inches inside the shell of the drum aimed at the beater pedal. The other
microphone used on the kick drum was a Yamaha SKRM-100 Subkick; this was placed
outside of the drum shellslightly off-axis of the beater pedal. API 512c preamps were
used for both kick drum microphones. Additionallyan Empirical Labs EL8X Distressor
was used on the Audix D6 to add compression, as well as a GML 8200 to add EQ.
32


Figure 1.2 Kick Drum Microphone (Inside Drum Shell) Close Up
33


Two microphones were used on the snare drumone condenser and one dynamic.
An Audix i5 (dynamic) was used on the top head of the dmm, roughly an inch to an inch
and a half away from the rimangled down at the drumhead. A Neumann KM86
(condenser) was used on the bottom head of the snare. This microphone was used in the
cardioid pattern, about an inch away from the dmmhead. API 512c preamps were used
for both snare microphones. Additionally, an Empirical Labs EL8X Distressor was used
to add compression, and a GML 8200 was used to add EQ on the Audix i5 microphone
(top dmmhead).
Figure 1.3 Snare Drum Microphone Placement (Bottom)
34


Figure 1.4 Snare Drum Microphone Placement (Top)


The drum set featured three tomsa floor tom and two rack toms (small and
large). Three Sennheiser 421s were used to record the top drumhead of the toms
whereas three Shure SM57s were used to record the bottom drumhead. The Sennheiser
42l5s were placed roughly an inch or so away from the rim, angled down at the
drumhead. The Shure SM57s were placed roughly at the center of the drumheadabout
an inch away from the head. API 512c preamps were used for the top dmmhead
microphones, whereas the preamps from the Euphonix CA200OP were used for the
bottom dmmhead microphones. No compression or EQ was used on the tom
microphones
Figure 1.5 Tom Microphone Placement Angle 1(Top)
36


Figure 1.7 Floor Tom Microphone Placement Close Up (Bottom)
37


Figure 1.9 Small Rack Tom Microphone Placement Close Up (Top)
38


Figure 1.10 Small Rack Tom Microphone Placement Close Up (Bottom)
Figure 111 Large Rack Tom Microphone Placement Close Up (Bottom)
39


Figure 1.12 Tom Microphone Placement Angle 2 (Top)


Several microphones were used for overhead and room microphones. A spaced
pair of Neumann U875s was used as a stereo left and right overhead. Both microphones
were used in the cardioid positionplaced roughly four to five feet above the drum kit. A
center overhead was also used, and for this I chose to use the Royer R-122, a phantom
powered ribbon microphone. This microphone was placed over the center of the drum kit
roughly four to five feet above the drum set. Three microphones were also used as room
microphones. Two AKG C4145s were used as far left and far right room microphones, in
the figure eight pattern. These microphones were placed roughly 15 feet away from the
drum setroughly six feet off the ground. A center room microphone was also usedand
for this I chose to use a Neumann 147 tube condenser. This was placed roughly 10 feet
away from the drum setaligned with the kick drum. This microphone was roughly six
feet off the ground. Brent Averill 1073 preamps were used on the Neumann U87
overheads, Neve 1073 preamps were used on the AKG C414 room microphones, and
Vintech X81 preamps were used on the center room microphone (Neumann 147) and
center overhead microphone (Royer R-122). Additionally, a Smart Research C2 stereo
compressor was used on the Neumann U87 overheads. A Tube Tech LCA2A stereo
compressor was used on the AKG C414 room microphones, and a Urei 1176LN
compressor/limiter was used on the Neumann 147 microphone. No EQ or other
processors were used on these microphones.
41


Figure 1.14 Drum Kit Overhead Microphone Placement Angle 2


An AKG C451B was used on the hi-hat. This cardioid condenser microphone was
placed roughly 6 inches above the hi-hat. A preamp from the Euphonix CA200OP was
used, and no additional processing was applied to this microphone.
Figure 1.15 Hi-Hat Microphone Placement
43


Figure 1.16 Tube Tech LCA2A Settings (Channel1)
Figure 1.17 Tube Tech LCA2A Settings (Channel 2)
Figure 1.18 Smart Research C2 Settings
44


Figure 1.20 Empirical Labs EL8X Distressor Settings


merfei 78
Figure 1.21 Urei 1176 LN Settings (*only top unit used)
Figure 1.22 Urei 1176 LN Settings
46


Figure 1.23 GML 8200 EQ Settings Left Channel Angle 1(Kick, In)
Figure 1.24 GML 8200 EQ Settings Left Channel Angle 2 (Kick, In)


Figure 1.25 GML 8200 EQ Settings Right Channel Angle 1(Snare Top)
Figure 1.26 GML 8200 EQ Settings Right Channel Angle 2 (Snare Top)
48


Figure 1.28 Otari MTR-90 24-Track Analog Tape Machine
49


Table LI Equipment Used at Colorado Sound (7/15-7/16)
Manufacturer Model Number Used Use Other Info.
Audix D6 1 Kick Drum, In Dynamic Microphone
Yamaha SKRM-100 Subkick 1 Kick Drum, Out Dynamic Micorpohne
Audix i5 1 Snare Drum, Top Dynamic Microphone
Neumann KM86 1 Snare Drum, Bottom Condenser Microphone
Sennheiser MD421 3 Floor and Rack Toms, Top Dynamic Microphones
Shure SM57 3 Floor and Rack Toms, Bottom Dynamic Microphones
AKG C451B 1 Hi-Hat Condenser Microphone
Neumann U87 2 Overhead, Left and Right Condenser Microphones
AKG C414 2 Room, Left and Right Condenser Microphones
Neumann 147 1 Room, Center Tube Condenser Microphone
Royer R-122 1 Overhead, Center Ribbon Microphone
API 512C 6 Kick (D6 & Subkick), Snare (i5 & KM86), Toms (Floor and Rack Toms, Top) Microphone Preamplifiers
Neve 1073 2 AKGC414s Microphone Preamplifiers
Vintech X81 2 Neumann 147, Royer R-122 Microphone Preamplifiers
Brent Averill 1073 2 Neumann U87s Microphone Preamplifiers
GML 8200 1 Kick (D6), Snare (i5) Stereo Equalizer
Urei 1176LN 1 Neumann 147 Compressor / Limiter
Tube Tech LCA2A 1 AKGC414s Stereo Compressor
Smart Research C2 1 Neumann U87s Stereo Compressor
Empirical Labs EL8X 2 Kick (D6), Snare (i5) Compressor
Apple Mac Pro 1 Digital Recording Computer
Avid Pro Tools 10 1 Digital Recording DAW Software
Avid/Digidesign 192 I/O 4 A/D Conversion, D/A Conversion, Word Clock, etc. DAW Interfaces
Otari MTR-90 1 Tape Recording 24-Track Analog Tape Macmne
50


Table LI Equipment Used at Colorado Sound (7/15-7/16) Continued
Manufacturer Model Number Used Use Other Info.
Euphonix CA200OP 1 Microphone Preamplifiers used on Toms Bottom (SM57s)Hi-Hat (C451). Used for splitting signal between DAW and tape machine Digitally Controlled Analog Console
Analog Tape Emulation
With a resurgence in popularity, many manufacturers have taken to creating
analog tape plug-ins, and a few have even created analog tape hardware devices. Some of
the more popular plug-ins includes the Eddie Kramer Master Tape from Waves, Slate
Digital Virtual Tape Machines, Universal Audio Ampex ATR-102 Mastering Tape
Recorder and Studer A800 Multichannel Tape Recorder There are countless other plug-
ins, with some ranging from being more of a novelty, to others getting close to being an
exact replication of tape. Rupert Neve Designs were one of the first to create an analog
hardware replication of a tape machine with their 5042 and 542 pieces of equipment.
Other hardware manufacturers include Crane Song and their Hedd 192, as well as
Anamod and their ATS-1. These pieces of equipment and plug-ins all aim at giving the
engineer the unique sound of tape, without the hassles associated with tape. The question
becomes, if these plug-ins and hardware devices can accurately emulate analog tape, is
there still a use for analog tape in the professional or project studio?
Slate Digital Virtual Tape Machines Plug-In. Slate Digital and head algorithm
developer Fabrice Gabriel created their Virtual Tape Machines (VTM) plug-in after more
than a year of research. The goal was to create the most authentic replication of an analog
51


tape machine in a digital plug-in format. The plug-in can be used as a 2-inch, 16-track
tape deckor 2-track tape deck. According to Steven Slatethe creator of Slate
DigitalYour mixes will come to life. Things will be easier to balance. Tracks will need
less EQ and compression. Depthspaceand warmth will be achieved like youve never
heard before.
The 2-inch 16-track is based off the famous Studer A827 with 16-track headstock
from NRG Recording Studios. This specific tape machine has been used on countless
best selling albums, and is a great tracking machine. The sound of this machine can be
characterized as having a Fatpunchythick sound with a very detailed top end. The
2-track is based off the Studer A80 RC with headstock from Howie Weinberg
Mastering. The sound of this machine can be characterized as having A thick low end
nice midrange, and a smooth top that perfectly takes away the digital edge in the most
natural way.
Additionally, the plug-in was modeled after two formulations of tape, the more
classic 456, and the more modern GP9. 456 tapes began being produced in 1975 and
were marketed as a high output tapewhich enabled the tape to handle higher
headroom available by the new tape machines being produced at the same time. 456 is a
+6tapewhich basically gives you an additional 6dB of headroom before any tape
saturation occurs. GP9 tape was produced much laterand was known as +9tape; this
tape became very popular due to the fact that you could record at higher levels without
the artifacts associated with tape such as saturation and distortion. These two tapes have
different qualities, the 456 is characterized as being more colorful, while GP9 is known
for being more punchy due to the fact it has more headroom.
52


While a lot of detail went into replicating the tape formulations, there was also a
lot of care given to the specifics of the tape machines such as tape speeds, bias, noise
reduction, and wow and flutter VTM can be used at two different tape speeds, 15ips
(inches per second) and 30ips. 30ips is known for having less noise, flatter frequency
response, and an extended high-end. Steven Slate recommends this speed 'Tor a pristine
sounding high-end with smooth saturation on peaks, and a nice thickening of the upper
low-end. 15ips is often known for sounding fatter but it also has a higher noise floor.
The mid-range of 15ips is also slightly extended giving this speed more mid-range
presenceor bite.
Bias can also be manually adjustedor used in the normal setting. There are also
two additional bias settings, one above and one below the recommended bias values.
With bias set to high, high frequencies saturate earlier, and when set to low, high
frequencies will saturate later with increased dynamics. Additionally, VTM is packed full
of extra features such as noise reduction and hiss automute, which automatically mutes
tape hiss when no signal is present. Noise reduction defaults to -3dB, but when using
VTM on multiple tracks of a mix, the hiss can become overwhelming. The noise
reduction feature was built in to give the ability to reduce the amount of tape hiss.
One of the other interesting features built into VTM is Wow and Flutter, and is
intended to emulate subtle pitch and amplitude variations inherent in a real tape machine.
This setting can be adjusted from 0% (off) to 100%, with Steven Slate claiming most
carefully maintained machines being around the 25% setting. Calibration levels can also
be user defined, which can give the user more saturation, and better signal-to-noise ratio,
or less saturation and more noise. The recommended signal chain when mixing is using
53


the 2-inch, 16-track VTM as the first plug-in on all tracks, and then using eq, etc, with the
y two-track on the master bus.
Rupert Neve Designs 5042/542. The Rupert Neve Designs (RND) 5042 is part of their
Portico seriesand is a true tape emulator and line driver. While there is no tape used in
the unitThe Portico 5042 incorporates an actual tape drive circuit that feeds a tiny
magnetic head whichin turnis coupled to a correctly equalizedreplay amplifier
[21].The design of this non-linear circuit offers the user the ability to add low-frequency
distortion (mostly third harmonic), as well as a boost to around 300 Hz [20]. These
effects are similar to what even the most well maintained tape machines produce. The
unit can also be bypassed, and used as a line driver. This simulates a technique in which
an engineer will pass audio through a tape machine without actually recording to tape.
This can help the engineer capture the sound of the electronics used in the tape machine
and add a desired fullness to their recording [20, 21].
The 5042 was originally released as a half-rack unit with included power supply
and input/output routing on the back of the unit. The 542 recently debuted as a 500 series
module, and uses many of the same features as the 5042. The 5042 has the ability to
switch between two tape speeds, 7.5 IPS or 15 IPS, each tape speed affects the sound
source differently. One review of the unit described the 7.5 IPS setting as chunkier and
duller whereas the 15 IPS setting was tighter and clearer. With the 15 IPS setting used
on a kick drumthe reviews found the kick drum to sound fuller and have an added low-
end presence. When used on cymbals, it tended to reduce edginess and make them sound
more polished and natural. There was also a consensus that it reduced sibilance on vocal
tracks [20, 21].
54


Aside from tape speed, the 5042 offers the ability to control the amount of record
level, essentially the amount of tape saturation. When the input level is increased, the
output level is simultaneously decreased. The circuitry of the 5042 adds coloration to the
sound source; even with the saturation control turned completely anti-clockwise, a slight
coloration can be heard. Correct gain structure is important when using the 5042, as the
input signal level will affect the amount of coloration. Turning the saturation control up
will increase harmonic distortion and transient compression. This can be done subtlety, or
more extreme to produce an overdriven and saturated sound. This effect is meant to
mimic driving an analog tape machine [20, 21].
Overall the consensus of the 5042 is that it very closely mimics a real analog tape
machine. It can help smooth over a recording and make a digital recording sound less
linear or sterile. It can also add extra low frequency weight and fullness while
remaining dynamic. The 5042 is very simple, easy to use, and only requires half a rack
space for a two-channel module. Perhaps the only downside to the 5042 is there are
limited meters, and the unit is not based off any particular tape machine, rather it is meant
to emulate the general effects produced by one [20, 21].
Post Tracking Procedures
Upon completion of all tracking, the output of the MTR-90 tape machine was
routed into new tracks in Pro Tools. This audio was recorded at 24 bit, 96 kHz into the
same session as the digital drum recording. Once the tracks were time aligneda duplicate
of all the rawunprocessed digital tracks was made. One set of digital drum tracks was
left unprocessed, while the other set had the Slate Digital VTM plug-in applied to each
track. Lastly, the unprocessed digital tracks were routed through the Rupert Neve Designs
55


5042 tape emulator, with the output recorded back into Pro Tools. This gave me four
different versions of the same recording; the original digital recording, the original analog
tape recording, the digital recording with VTM applied, and the digital recording
processed by the 5042.
Settings varied on the RND 5042; some drums required more saturation than
others to sound like their analog equivalent. Settings on the VTM plug-in were roughly
the same on each track, with slight input and output levels being fine-tuned as needed.
Slight level (volume) adjustments were also needed in order for all tracks to have roughly
the same overall level. This was an important step; a perceived level difference could
unintentionally persuade the listener into thinking the louder version sounds better
Table 1.2 Equipment List For Tape Emulation
Manufacturer Model Use Other Info.
Rupert Neve Designs 5042 Hardware Tape Emulation 2 Channel Tape Emulator
Avid/Digidesign 192 I/O A/D Conversion, D/A Conversion, Word Clock, etc. DAW Interfaces
Avid Pro Tools 10 All audio processing tasks DAW Software
Apple Mac Pro Pro Tools Computer
Slate Digital Virtual Tape Machines Software Tape Emulation DAW Plug-In
56


7.5 IPS
15 IPS
METER
INPUT
TAPE
SATURATION
Figure II.1 5042 Emulation on Kick Drum (Audix D6)
^5 IPS >
METER
INPUT
TAPE ^
SATURATION
22
18
M
10
6
4
2
0
LINE
UP
ENGAGE
^TAPE
OdB
TAPE A
Figure 112 5042 Emulation on Kick Drum (Yamaha Subkick)
57



SATU
METER
INPUT a MIN MAX
TAPE % 1)' TO A
BUSS
22 _ ENGAGE
UNE
UP

TAPE
12
TAPE A
Figure 11.3 5042 Emulation on Snare Drum (Audix i5)
7.5 IPS ,
15 IPS >
METER
INPUT
TAPE

SATURATION
MIN MAX
TO A
BUSS
Figure 11.4 5042 Emulation on Snare Drum (Neumann KM86)


15 IPS : SATURATION
TAPE A
Figure 11.5 5042 Emulation on Floor Tom and Small Rack Tom (Sennheiser 421)
7.5 IPS
15 IPS .
METER
INPUT
TAPE

SATURATION
MIN
MAX

TO A
BUSS
Figure 11.6 5042 Emulation on Large Rack Tom (Sennheiser 421)
59


^ 5 IPS ^
METER
INPUT
TAPE

MIN MAX
TO A
BUSS
22
IB
14
10
6
4
2
0

ENGAGE
OdB
TAPE A
Figure 11.7 5042 Emulation on Hi-Hat and Center Room Microphone (Neumann 147)

METER
INPUT
TAPE

MIN MAX

TO A
BUSS
22
18
14
10
6
4
2
0
LINE
UP
ENGAGE
TAPE
OdB
0 TAPE A
Figure 11.8 5042 Emulation on Left Room Microphone (AKG C414)
60


Cn^l") Portico Series O
J v c. Tape Emulator
Tape B
7.5 IPS
15 IPS
METER
iNPUT
TAPE

SATURATION
MIN MAX

ENGAGE
^.TAPE
OdB
Figure 119 5042 Emulation on Right Room Microphone (AKG C414)
7.5 IPS
15 IPS
METER
INPUT
TAPE
MIN WAX
TO A
BUSS
ENGAGE
TAPE
OdB
# tape A ^
Figure 11.10 5042 Emulation on Left Overhead Microphone (Neumann U87)


prtico Series f)
c. Tape Emulator ___________
m tapeb ^

METER
INPUT 4 ,
TAPE
SATURATION
MIN MAX

TOB
BUSS
22
18
14
10
b
4
2
0
LINE
UP
ENGAGE
^ TAPE
OdB
Figure 11.11 5042 Emulation on Right Overhead Microphone (Neumann U87)


Figure 11.13 Slate Digital Virtual Tape Machines Calibration Settings
63


CHAPTER III
RESULTS
Through this study I have determined there are some aspects of analog tape that
are possible to recreate through the use of analog hardware and digital plug-ins. Digital
recording offers a flat frequency response at all frequencies, whereas with analog
recording, the combination of tape machine and tape speed will affect certain frequencies.
This is most evident in the low frequency ranges, with most machines giving a slight
boost to bass frequencies. This is one of the reasons people claim that drums recorded to
analog tape sound bigger or fuller. For this studyI believe this is the easiest factor to
recreate, especially with the analog hardware unit (RND 5042). The RND 5042 did bring
fullness to the kick drum that it seemed to be lacking in the digital recording.
Tape saturation is another effect many seek when recording to analog tape. I feel
this aspect is possible to achieve to some extent. Tape saturation is essentially a form of
compression. With tape saturation, transients are essentially rounded off, the harder the
tape is pushed, and the earlier the distortion will start to occur. With digital recording, if
there is not adequate headroom, the signal will clip. Digital audio is less forgiving in this
aspect. The Slate Digital VTM plug-in allows the user to adjust how much tape saturation
they want. Similarly, the RND 5042 has a saturation adjustment control.I feel both of
these units performed this function fairly well. This recording did not feature any extreme
examples of tape saturation, and it is possible neither of the units would accurately
replicate a more severe example of tape saturation. I believe the VTM and RND 5042
added an acceptable level of saturation, especially on the snare tracks.
64


While the Slate Digital VTM plug-in is modeled after two somewhat famous
analog tape machines through the use of algorithms and programming, the Rupert Neve
Designs 5042 is modeled after the electronics of a tape machine. The advantage to using
the RND 5042 is that the audio is actually being passed through an analog signal chain,
with real analog components affecting the sound. This means actual harmonic distortion
is being applied to the audio, just as it would be if it were passing through an analog tape
machines electronics. I feel this is an advantage to the RND 5042, and creates a more
accurate tape sound. I feel both processors made the drum overhead and room
microphones sound fairly close to the analog tape recording, and made them sound a bit
more natural.
Wow and flutter are two other components needed to consider when
discussing an analog tape recording. Although several plug-ins have a Wow and Flutter
control, many claim this is not possible to replicate through emulation plug-ins. I feel this
is the hardest aspect to judgeand extremely dependent on the machine. Overall I dont
think it is entirely possible to recreate this phenomenon with a plug-in. Although the
Slate Digital VTM plug-in does attempt to create this effect, and give the user a range of
settings they can adjust, the RND 5042 does not offer this setting, and therefore is more
accurate in that sense.
The bottom line with analog tape is there are always going to be several factors at
play that affect the recorded sound; the way in which the tape machine was biased, the
amount of wow and flutter the type of tape usedetc. These factors are perhaps too
much to neatly program into a plug-in emulator, or analog hardware unit. While both of
the processors examined in this study aim to replicate analog tape, it may be impossible
65


to exactly replicate an analog tape machine because of all the variables involved. What
these processors do succeed at accomplishing is adding analog character to a recording.
The RND 5042 does this through an analog circuit, whereas the Slate Digital VTM plug-
in models an analog tape machine through complex algorithms.
To the experienced engineer that remains faithful to analog tape, these processors
may not achieve what the engineer is looking for when it comes to an analog recording.
Those who can take advantage of this technology are project studio engineers who either
do not have the space or the budget to incorporate a real analog tape machine into their
studio. While neither of these processors, or perhaps any analog tape emulator will give
the engineer the results of a real analog tape machine, they will certainly get them close.
They can also be used to improve the quality of a recording, and make a digital recording
sound less pristine if that is their goal. While the RND 5042 may seem like quite an
expense for a project studio owner, the Slate Digital VTM plug-in is more moderately
priced, and will achieve similar results. Through the use of this technology, as well as a
good analog and digital signal chain, project studio recordings can sound closer than ever
to the recordings being produced by a professional recording studio. In general, the
characteristics that engineers want to emulate from a tape machine are tape saturation,
frequency response, and 3rd harmonic distortion. Through the use of VTM or RND 5042,
one can come very close to reproducing these qualities in a digital recording. Overall I
preferred the RND 5042 and felt it more accurately emulated the analog tape recording.
While the VTM plug-in was very close as far as quality, its ease of use and cheaper price
tag make it an exception plug-in for any project studio engineer to own.
66


CHAPTER IV
CONCLUSIONS
Other Factors To Consider
There are many factors that could be changed in order to produce different results
with this study. The type of tape machine, calibration settings, and type of tape used, and
how much tape saturation occurs could all make these results vary. Otari tape machines
are known for being fairly neutral tape machines, whereas other manufacturers such as
Studer and Sony/MCI are known for having more character. Similarly, some engineers
claim 16-track machines perform better than 24-track machines. The way in which the
machine was calibrated can also be a huge factor A machine calibrated at +9 has an
additional 9 dB of headroom before tape saturation and distortion starts to occur, whereas
a machine calibrated at +3 only has an additional 3 dB of headroom.
While this study was only conducted with an acoustic dmmset, the same methods
could be applied to any instrument. Additionallythe genre of music used for this study
was rock, and other genres could be tested as well. Perhaps it would be inappropriate to
apply this study to a classical recording, but there are several genres that can benefit from
analog recording.
Final Thoughts
Digital audio has improved remarkably since its inception, and early
shortcomings have improved over time. Although professional grade digital audio
equipment remains costly, even the quality of cheaper digital audio equipment is
improving. With the rise of digital audio in home and project studios, the signal chain is
often an afterthought to some engineers. While it is certainly possible to acquire a simple
67


DAW setup involving a USB or Firewire interface and a computer, the results will hardly
be close to professional grade without considering the other elements in the signal chain.
The quality of the built in preamplifiers in many DAW interfaces is often subpar, and
cramming too many elements (A/D, D/A converters, word clock, etc.) into one rack
enclosure can often lead to compromises of quality. Modular systems have given the
project studio the ability to incorporate analog hardware into their signal chain, without
having to purchase a large format analog console. Other equipment such as analog
summing boxes allow for an easy and convenient method for analog mixing. While it is
getting harder and harder to argue against the quality of digital recording, both the analog
and digital signal chains are important to consider when setting up a project studio; one
weak link can compromise the quality of a recording. Only a few of the elements needed
to construct a professional grade project studio are considered in this portfolio; other
elements such as acoustic treatment and monitoring are not considered but are quite
possibly just as important.
Although many have made the switch from analog to digital, some engineers and
musicians remain faithful to analog technology and recording. This leads to an interesting
discussion, as to whether or not the qualities associated with analog tape can be
reproduced through the use of analog hardware emulation or digital plug-in emulation.
Through this portfolio I have found that some of the desired qualities can be achieved
through the use of analog hardware and plug-in emulation. While only one plug-in and
one hardware emulator were tested, these two emulators show the direction the industry
is headed towards, and improvement on these designs is imminent.
68


The goal of this portfolio is not to determine which recording medium produces a
higher quality recording, but rather to determine if recording technology is at the point
where digital recording can produce similar results to an analog recording. I feel through
the use of a hybrid recording setup, many of the desired results of analog recording can
be achieved through the use of digital recording, and analog tape emulation. The music
industry is shifting towards digitally released albums and singles, and the majority of
listeners are using subpar playback systems or mobile devices. Although this is a
discouraging trend, we as engineers should always strive to produce the highest quality
recordings, regardless of how the listeners intend to playback the recording.
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http://mikeriversaudio.files.wordpress.com/2010/10/micpreampsagain updated.pdf
23. Jung, W. (2004). Op amp applications handbook. (1st ed., pp. 767-771).
Burlington, MA: Newnes.
24. Lavry, D. (2004). Sampling theory for digital audio. Retrieved from
http://lavryengineering.com/pdfs/lavry-sampling-theory.pdf
25. TingenP. (2005, September). Steve albini sound engineer extraordinaire.
Sound on Sound, Retrieved from
http://www.soundonsound.com/sos/sep05/articles/alDim.htm
2o.lingen, P. (2013, August). Secrets of the mix engineers: andrew scheps.
Sound on Sound, 25(10), 148-157.
27. Doyle, T. (2011, June). Foo fighters: Recording wasting light. Sound on
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Full Text

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ANALOG EMULATION AND INTEGRATION IN THE HYBRID STUDIO By JOSEPH MICHAEL HIDALGO B.S., University of Colorado Denver, 2010 A thesis submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requireme nts for the degree of Master of Science Recording Arts 2013

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ii This thesis for the Master of Science degree by Joseph Michael Hidalgo has been approved for the Recording Arts Program by Lorne Bregitzer, Chair Leslie Gaston Bird Doug Krause 11/15/13

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iii H idalgo, Joseph, Michael (M.S., Recording Arts) Analog Emulation and Integration in the Hybrid Studio Thesis directed by Professor Lorne Bregitzer. ABSTRACT This portfolio examines a practical approach to analog and digital hybrid recording. Comprehensive research is included to determine the advantages and disadvantages of each recording medium including a detailed history of each format. Analog integration in the project studio is researched in depth to determine practicality for the home studio engineer, including detailed research on modular recording hardware. Various mixing techniques including mixing in the box versus mixing out of the box and analog summing versus digital summing are also analyzed. Analog tape software plug in and hardware emulation is examined to determine how accurate analog tape emulation actually is, including what elements can and cannot be reproduced through the use of software plug ins and analog hardware. To conduct this study, a simultaneous analog and digital recording of an acoustic drum kit was produced in order to compare a true analog tape recording and a digital recording modified through the use of analog hardware and software plug ins. The form and content of this abstract are approved. I recommend its publication. Approved: Lorne Bregitzer

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iv DEDICATION I dedicate this work to my mother and father, Michele and Greg Hidalgo. It was with their guidance, advice, love and support that I was able to complete this portfolio.

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v ACKNOW LEDGMENTS I would like to thank Max Boyd, Matt Best, Dan Gilbert and Dan Galanski for being a part of this project. I woul d also like to recognize the MEIS faculty and specifically Lorne Bregitzer, Leslie Gaston Bird and Doug Krause for their support and i nspiration over the years. Lastly, I would like to thank my grandparents, Esperanza and Zaragoza Hidalgo, Stephanie and Garrett Brown, and Monicque Aragon.

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vi TABLE OF CONTENTS CHAPTER I. INTRODUCTION ................................ ................................ ................................ .... 1 History ................................ ................................ ................................ ............................ 1 Birth of Magnetic Recording ................................ ................................ ........................... 1 B asic Components of Analog Tape ................................ ................................ .................. 2 Advantages of Analog Recording ................................ ................................ .................... 3 Disadvantages of Analog Recording ................................ ................................ ................ 6 Digital Recording ................................ ................................ ................................ ............ 8 Stationary Head Transport Versus Rotary Head Transport ................................ ... 8 Digital Audio Stationary Head, Pro Digi, and Digital Compact Cassette .............. 9 ADAT Recorders ................................ ................................ ................................ 9 The Digital Audio Workstation ................................ ................................ .......... 10 Basic Components of Digital Audio ................................ ................................ .............. 10 Sampling ................................ ................................ ................................ ........... 11 The Nyquist Theorem ................................ ................................ ........................ 11 Quantization ................................ ................................ ................................ ...... 11 Advantages of Digital Recording ................................ ................................ ................... 12 Disadvantages of Digital Recording ................................ ................................ ............... 13 The Analog and Digital Hybrid Studio ................................ ................................ .......... 15 Analog Int egration in the Project or Home Studio ................................ .......................... 16 Modular Systems ................................ ................................ ............................... 16 Analog Integration in the Recording Process ................................ ................................ 19 Modern Examples of Analog Recording ................................ ................................ ........ 22 Analog Integration in the Mixing and Mastering Process ................................ ............... 24

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vii Analog Summing Versus Digital Summing ................................ ........................ 25 Mixing In The Box Versus Out Of The Box ................................ ....................... 27 II. METHODS ................................ ................................ ................................ ............ 30 Purpose of the Study ................................ ................................ ................................ ...... 30 Overview ................................ ................................ ................................ ....................... 30 Analog Tape/Pro Tools Specifications ................................ ................................ ........... 30 Tracking Procedures ................................ ................................ ................................ ...... 32 Analog Tape Emulation ................................ ................................ ................................ 51 Slate Digital Virtual Tape Machines Plug In ................................ ................................ .. 51 Rupert Neve Designs 5042/542 ................................ ................................ .......... 54 Post Tracking Procedures ................................ ................................ .............................. 55 III. RESULTS ................................ ................................ ................................ .............. 64 IV. CONCLUSIONS ................................ ................................ ................................ .... 67 Other Factors To Consider ................................ ................................ ............................. 67 Final Thoughts ................................ ................................ ................................ .............. 67 REFERENCES ................................ ................................ ................................ .............. 70

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viii LIST OF TABLES Table I.1 Equipment Used At Colorado Sound (7/15 7/16) ................................ ...................... 50 I I.1 Equipment List For Tape Emulation ................................ ................................ ........ 56

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ix L IST OF FIGURES Figure I.1 Kick Drum Microphone Placement ................................ ................................ .......... 33 I.2 Kick Drum Microphone (Inside Drum Shell) Close Up ................................ ........... 33 I.3 Snare Drum Microphone Placement (Bottom) ................................ ......................... 34 I.4 Snare Drum Microphone Placement (Top) ................................ ............................... 35 I.5 Tom Microphone Placement Angle 1 (Top ) ................................ ............................. 36 I.6 Floor Tom Microphone Placement Close Up (Top) ................................ ................. 37 I.7 Floor Tom Microphone Placement Close Up (Bottom) ................................ ............ 37 I.8 Large Rack Tom Microphone Placement Close Up (Top) ................................ ........ 38 I.9 Small Rack Tom Microphone Placement Close Up (Top) ................................ ........ 38 I.10 Ssmall Rack Tom Microphone Placement Close Up (Bottom) ............................... 39 I.11 Large Rack Tom Microphone Placement Close Up (Bottom) ................................ 39 I.12 Tom Microphone Placement Angle 2 (Top) ................................ ........................... 40 I.13 Drum Kit Overhead Microphone Placement Angle 1 ................................ ............. 42 I.14 Drum Kit Overhead Microphone Placement An gle 2 ................................ ............. 42 I.15 Hi Hat Microphone Placement ................................ ................................ .............. 43 I.16 Tube Tech LCA2A Settings (Channel 1) ................................ ............................... 44 I.17 Tube Tech LCA2A Settings (Channel 2) ................................ ............................... 44 I.18 Ssmart Research C2 Settings ................................ ................................ ................. 44 I.19 Empirical Labs EL8X Distressor Settings ................................ .............................. 45 I.20 Empirical Labs EL8X Distre ssor Settings ................................ .............................. 45 I.21 Urei 1176 LN Settings ................................ ................................ ........................... 46 I.22 Urei 1176 LN Settings ................................ ................................ ........................... 46

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x I.23 GML 8200 EQ Settings Left Channel Angle 1 (Kick, In) ................................ ....... 47 I.24 GML 8200 EQ Settings Left Channel Angle 2 (Kick, In) ................................ ....... 47 I.25 GML 8200 EQ Settings Right Channel Angle 1 (Sn are Top) ................................ 48 I.26 GML 8200 EQ Setting Right Channel Angle 2 (Snare Top) ................................ ... 48 I.27 DAW Interfaces ................................ ................................ ................................ .... 49 I.28 Otari MTR 90 24 Track Analog Tape Machine ................................ ..................... 49 II.1 5042 Emulation On Kick Drum (Audix D6) ................................ ........................... 57 II.2 5042 Emulation On Kick Drum (Yamaha Subkick) ................................ ................ 57 II.3 5042 Emulation On Snare Drum (Audix i5) ................................ ........................... 58 II.4 5042 Emulation On Ssnare Drum (Neumann KM86) ................................ ............. 58 II.5 5042 Emulation On Floor Tom And Small Rack Tom (Sennheiser 421) ................. 59 II.6 5042 Emulation On Large Rack Tom (Sennheiser 421) ................................ .......... 59 II.7 5042 Emulation On H i Hat And Center Room Microphone (Neumann 147) .......... 60 II.8 5042 Emulation On Left Room Microphone (AKG C414) ................................ ..... 60 II.9 5042 Emulation On Right Room Microphone (AKG C414) ................................ ... 61 II.10 5042 Emulation On Left Overhead Microphone (Neumann U87) ......................... 61 II.11 5042 Emulatio n On Right Overhead Microphone (Neumann U87) ....................... 62 II.12 Slate Digital Virtual Tape Machines Settings ................................ ........................ 63 II.13 Slate Digital Virtual Tape Machines Calibration Settings ................................ ...... 63

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xi LIST OF ABBREVIATIONS A/D Analog to Digital CD Compact Disc CPU Central Proc essing Unit D/A Digital to Analog DASH Digital Audio Stationary Head DAT Digital Audio Tape DAW Digital Audio Workstation DB Decibels DCC Digital Compact Cassette IPS Inches Per Second MDM Modular Digital Multi Track MTRs Multi Track Recorde rs NOS New Old Stock nWb/m NanoWebers Per Meter Op Amp Operational Amplifier PCM Pulse Code Modulation Preamp Preamplifier RND Rupert Neve Designs VTM Virtual Tape Machine

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1 CHAPTER I INTRODUCTION History Thomas Edison produced the earliest known recordings in 1877. With the help of John Kruesi, Edison used a tinfoil cylinder phonograph to record the human voice. Early recording technology would continue to develop, with various innovators experimenting with different materials for the cylinder pho nograph. In 1878 Frank Lambert used a lead cylinder, which is known as the oldest, surviving playable recording. In 1885, Chichester Bell and Charles Tainter would invent the Graphophone, a machine that used wax coated cylinders with vertical cut grooves. Emile Berliner improved on the early phonographs, and in 1887 created the Gramophone, which used a flat, hard rubber disk that contained lateral cut grooves on one side. These disks could then be mass produced using a zinc master disk. By the 1890's, impro ved versions of the graphophone and gramophone were in production, and cylinders and disks were being sold to the public along with jukeboxes [1]. Birth of Magnetic Recording In 1898, Vlademer Poulsen invented the first magnetic recording device. The devi ce used steel wire, and Poulsen called it the Telegraphone. Dr. Fritz Pfleumer patented the idea of putting magnetic powders onto paper or film in 1928, and by 1931, Pfleumer and German based electronics company AEG began building the first magnetic tape r ecorders. In 1935, German chemical company BASF along with AEG debuted their Magnetophon to the public, and in 1936 BASF/AEG would record the first live concert

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2 onto magnetic tape. Also at that time, BASF had begun manufacturing plastic based magnetic tape Up until this point, the United States had not developed magnetic recording outside of wire recorders. In 1944, the 3M Company (Minnesota Mining and Manufacturing) started to experiment with magnetic tape coating in the United States [1]. Magnetic tape recorders arrived in the United States in 1945; U.S. Signal Corps Captain John Mullin found magnetophones at Radio Frankfurt in Germany along with 1000 meter reels of BASF tape. Mullin sent two of the magnetophones along with 50 reels of tape to the United States; he worked on improving the electronics after returning from WWII. Mullin demonstrated the magnetophon to Bing Crosby in 1947; ABC and Philco began taping the Crosby show with one of the magnetophones, and by 1948 the first U.S. made Ampex Model 20 0 magnetic tape machines were in production. By the 1950's, recording studios were using analog tape machines, and musicians such as Elvis Presley and Bill Haley were releasing rock and roll records [1]. Basic Components of Analog Tape The analog tape mac hine transforms an electric input into magnetic energy; magnetic energy is then stored on the tape as magnetic remnants. For playback, magnetic energy is converted into an electric signal, which can be amplified for playback [2]. Analog tape formulations c hanged and improved over the years; 3M Scotch 111 gamma ferric oxide coated acetate tape was used in the early years of the Bing Crosby show [1]. Modern tape formulations are made up of four layers; the base is made of either polyester or polyvinyl chlorid e (PVC). The base layer provides most of the bulk of the tape, and is a durable material that protects the tape from much of the abuse it receives from being run through the tape machine. The most significant component of the tape is the magnetic

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3 oxide bon ded to the base layer; these tiny magnetic particles are called domains. When a reel of tape is unmagnetized, the polarities of the domains are randomly organized across the surface of the tape. Due to the random magnetization of the domains, when the tape is passed through the reproduce head, the result is a cancellation of the combined domain energies. Aside from tape noise due to residual domain energy, no signal is produced at the tape machine's output. When signal is recorded onto the tape, the record head polarizes the individual domains in positive and negative directions; the domains combine to create magnetic flux. When the tape is passed through the playback head at the same speed in which it was recorded, the alternating magnetic output is convert ed back into an alternating signal. The other com ponents of the tape include a ta p e coating and an anti static backing [2]. Advantages of Analog Recording According to Bob Katz, "A finely tuned 30 IPS !" tape recorder is more accurate, better resolved, ha s better space, depth, purity of tone and transparency than many digital systems available today." Katz also believes that !" tape has a greater bandwidth than 44.1 kHz or 48 kHz digital audio, requiring the need for high sample rate sessions. There is als o the argument that analog distortion is far more "pleasant" than digital distortion. Analog distortion gradually and gently obscures ambience and low level material, whereas digital distortion due to rounding errors in digital filters or other elements in the digital signal chain can sound considerably unpleasant [2]. According to Hugh Robjohns, there are a number of factors that can lead to an analog recording sounding "warmer" than a digital recording. Analog electronics may add tonal qualities to a re cording; transformers and inductors cause harmonic and non

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4 harmonic distortions. These characteristics can be captured somewhat with digital recording through the use of analog preamplifiers, and tube microphones; Katz refers to this process as adding a "w arm and fuzzy band aid" to a recording. When recording with an analog tape machine, there are additional factors to consider regarding how the sound is affected. There are certain mechanical factors caused by the tape machine, such as "wow" and "flutter," and other speed stability issues. There are several speed variations caused by an analog tape machine, which occur at different frequency ranges. These variations include "drift" (below 0.1Hz), "wow" (0.1 10Hz), "flutter" (10 100Hz), and "scrape flutter" (1 5kHz). While these instabilities were remedied to some extent over the years, they are impossible to completely remove from a tape machine. The Studer A820 two track machine, one of the most sought after tape machines even to this day, had a measurable wow and flutter figure of 0.04 percent when running at 15 IPS. In the digital realm, word clock instability is the equivalent of wow and flutter; in a good digital system, word clock stability is immeasurable [3]. Wow and flutter affects the recorded audio by creating subtle "side bands" and noise modulation around the audio. This modulation adds a low level "grunge" to the audio; although well maintained machines add less of this "grunge," it still occurs at some extent. Bounce downs and overdubs can also multiply this effect, as it is a cumulative effect. According to Hugh Robjohns, wow and flutter are not possible to replicate in a digital recording, and one of the reasons many engineers have remained faithful to analog tape recording. Another artifact c reated by analog tape recording is a phenomenon called tape saturation, or tape compression. Tape saturation occurs when the recorded signal peaks

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5 above 0 dB VU. The result is a rounding off of the transient, due to the physical limitation of the tape. As the signal level reaches 0 dB VU, the magnetization of the tape drops, and compression begins to occur. This is a smooth and gradual process, resulting in the rounding off of the transients. The result is the creation of odd harmonics in the distorted sig nal, mainly the 3 rd harmonic. Unlike distortion in the digital realm, this kind of distortion sounds very "musical" and some instruments such as rock drums, guitar and bass can actually benefit from this effect as long as it is not overdone. Each instrumen t will require different amounts of tape saturation, and that can be adjusted by how hard the signal to the tape is driven [28]. Flux is also a factor when dealing with tape saturation; flux is defined as, "The amount of density of magnetic particles on t ape per meter (nWb/m)" [28]. Flux is measured in NanoWebers per meter (nWb/m), a higher flux level equates to more level that can be recorded onto the tape. Modern tape formulations enabled higher recording levels with minimal tape saturation. When calibra ting a tape machine an operating level must be chosen. In general, the higher the operating level, the further you are away from the noise floor, but you are also closer to the point of distortion (tape saturation). Ampex initially created a standard recor ding level, known as "Ampex 0" or "Ampex Operating Level" in 1950. Ampex 0 is equivalent to 185 nWb/m, and all early alignment tapes followed this standard. As tape formulations improved and were more capable of handling higher levels, Ampex 0 was still re ferenced. For example, a tape designed to record levels at 250 nWb/m were known as "+3" and thus could handle an additional 3 dB of headroom before distorting [28].

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6 "Analogue recording tape is inherently non linear', its effect being determined by a comb ination of tape formulation, record and replay head construction, tape speed, tape width, record and playback equalisations (and phase shifts), and the level and waveform of high frequency bias" [3]. These factors introduce harmonic distortions (at low fre quencies), frequency and phase irregularities and more importantly, reduce dynamic range. Self erasure and magnetic saturation mainly affect high frequency transients. In order to avoid low and mid frequency harmonic distortions, tape machines can be "over biased;" the trade off being at the expense of high frequency extension and transient accuracy. While it could be argued that this is a negative effect of analog tape recording, this imperfect characteristic of analog tape recording is said to sound more natural than a near perfect digital recording [3]. Disadvantages of Analog Recording Katz neatly summarizes the biggest disadvantage of analog recording, "analog requires constant vigilance to sound good" [5]. Analog tape machines require consistent main tenance, including biasing, calibration, and cleaning to function to their fullest extent. Another important consideration is cost; some important factors to consider are the price of the machine, parts and labor, transportation or shipping costs, as well as the cost of tape. There are currently no new analog tape machines being manufactured, which means the market consists of used machines that range in condition. Some manufacturers such as Otari have remained in business and continue to produce parts for their machines, while other 3 rd party companies have begun to produce replacement parts for a number of the more popular tape machines. Tape manufacturers have also become more rare, though there are currently a handful that are producing new reels. RMG In ternational, a company

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7 based out of the Netherlands, and ATR Magnetics from York, Pennsylvania are two of the remaining tape manufacturers. New Old Stock (NOS) tape can also be purchased, which is essentially old, unused tape from the heyday of analog tape recording. Used reels can also be purchased at a discount, but it is generally unwise to re use a reel more than three times. Flexibility is another issue when working with analog tape recorders. Analog editing is possible, through the use of a razor bl ade and splicing tape. While this type of editing is more time consuming and perhaps less precise than digital editing, it isn't impossible, and splicing was once a necessary skill for audio engineers. Another issue with analog tape recording is track coun t. In a good digital audio system, track count is rarely an issue, and most systems provide a nearly unlimited number of tracks. With analog recording, the track count is based on the machine and reel of tape. Professional multi track tape recorders were g enerally produced in 8, 16, or 24 track configurations using either one or two inch tape. In the earlier days of analog tape, 4 track machines were the standard. When the Beatles recorded many of their classic albums, only two track and four track machines were available. To work around this limitation they used a process called submixing. If a four track reel was full, they would submix these existing tracks to one or two tracks on a new four track machine. While this method worked, it meant several instru ments had to be summed together onto a single mono track, and EQ, levels and effects were recorded directly to tape, and thus couldn't be undone [8]. This process was used even when 24 track tape machines were the standard for commercial recording studios; often times two 24 track tape machines would be used for recording and bouncing down. The Smashing Pumpkins and producer Butch Vig used two 24 track

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8 Studer tape machines to record the album Siamese Dream in 1992. Some songs had as many as 40 guitar parts, so bouncing down to a second machine was essential in the production of this album [9]. Digital Recording While the ability to record using a digital device was not developed until many years later, Alec H. Reeves invented pulse code modulation (PCM) in 1 937 while working for the International Telephone and Telegraph Co. in France. Bell Labs and other telecommunication companies used PCM sporadically over the years; it wasn't until 1972 that the Nippon Columbia Co. invented a PCM recorder. This recorder wa s used to master soundtracks, and audio was stored on videotape, which roughly contained 87 dB of dynamic range. Around this time period, others were experimenting with digital audio. In 1962 Tom Stockham of MIT was creating digital audio tape recordings u sing a TX 0 computer and analog to digital (A/D), digital to analog (D/A) converter created by Bernie Gordon of EPSCO. In 1975, Stockham and Malcolm Lee founded Soundstream, and created a 16 bit digital audio recorder. While digital audio was being experim ented with, it wasn't a practical method of recording until Sony/Phillips introduced the Digital Audio Tape (DAT) in 1986. DAT recorders use a tape smaller than a standard cassette tape, and offered the ability to record at sampling frequencies of 32, 44.1 and 48 kHz [2]. Stationary Head Transport Versus Rotary Head Transport Stationary head recorders used technology similar to analog tape recorders. One of the reasons for their popularity was that they were cheap to produce. The downside was they offered low head to tape speed, which either meant a low data transfer rate, a very high density of data on the tape, or both situations occurring. Rotary head machines essentially had the

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9 opposite characteristics; high head to tape speeds, high data transfer rat es, and lower data density on tape. Lower data density on the tape reduced the demands on the tape itself. In the early days of digital recording, manufacturers had enough issues creating accurate A/D and D/A converters, and thus chose to use existing vide o recorder technology (rotary head transport), rather than reinvent the transport head. Although the majority of CD mastering recorders used video transports to store digital audio, Sony, Studer, Mitsubishi and Philips created stationary head digital recor ders [7]. Digital Audio Stationary Head, Pro Digi, and Digital Compact Cassette. Stationary head recorders became the dominant 24 and 48 track digital recorders in the early years of digital recording. Mitsubishi invented Pro Digi (PD), and offered machin es in 2, 16, and 32 track formats using quarter inch, half inch, and 1 inch tape. Although the PD machines were popular for some time, Mitsubishi stopped production as Sony's Digital Audio Stationary Head (DASH) format gained popularity in the stationary h ead market. DASH recorders were available in 2, 24 and 48 track versions, with the first models appearing in 1987. DASH recorders were eventually capable of recording at 24 bit. Philips invented the Digital Compact Cassette (DCC) as a means to replace the analog compact cassette. DCC was invented around the same time as DAT; the two formats were referred to as R DAT and S DAT (Rotary head and Stationary head). DCC was more of a consumer "hi fi" format but never gained too much popularity due to the popular ity of CDs and Minidiscs [7]. ADAT Recorders. The next advance in digital recording was the creation of the ADAT recorder, which was invented by the Alesis Corporation in 1991. Each ADAT machine could record 8 tracks to a S VHS videocassette, and up to 16 ADAT machines could be

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10 connected together enabling the user to record a total of 128 tracks. In 1992, Tascam released the DA 88, the first modular digital multi track (MDM), which used Hi 8 videotape [1]. According to Modern Recording Techniques MDM reco rders were responsible for the switch from analog recording to digital recording in professional recording studios. Over the years other digital recording technologies were invented including ADAT MDM recorders, the Digital Tape Recording System, as well a s hard disk recorders and MiniDisc recorders [2]. With the exception of hard disk recording units, most of the early digital audio recorders have been taken out of production, mostly in favor of the Digital Audio Workstation (DAW). The Digital Audio Workst ation. A DAW is a computer based hard disk recording system, usually integrated with an audio interface that acts as an A/D, D/A. Some interfaces also include microphone preamplifiers, MIDI interconnectivity, monitor and headphone controls, as well as othe r features. DAW software allows the user to record, edit and mix, as well as sequence MIDI, and use virtual instruments. DAW software also allows the user to affect the audio with "plug ins." Plug ins often act to replicate processes done in the analog wor ld such as equalization, compression, and many other effects. Popular DAW software includes Avid's Pro Tools, Apple's Logic Pro, Steinberg's Cubase, as well as many other programs that all feature their own unique benefits. Basic Components of Digital Aud io The two basic components of sound are frequency (component of time) and amplitude (signal level); in digital audio these two components are sampling (component of time) and quantization (signal level). Unlike analog recording, digital recording does

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11 not occur in a continuous manner; instead it uses a process where it takes periodical samples of an audio waveform. These sampled signal levels are transformed into a representative stream of binary words that can be stored and later manipulated. Sampling W ith a digital recording system, the user chooses a sample rate, which is the number of samples of analog signal taken in one second. Sample rate determines bandwidth; therefore a higher sample rate can store more frequencies at its upper limit. The recipro cal of sample rate is sample time, or the elapsed time between each sampling period. A commonly used sample rate of 48 kHz would correlate to a sample time of 1/48,000 th of a second. The sample rate determines what timed intervals the analog signal is samp led at. The analog signal is held at each interval, during this temporary hold the A/D converter determines what the voltage level of the signal is. The accuracy of this process is dependent on the circuitry used in the converter and the bit rate. The Nyq uist Theorem. Dr. Nyquist discovered his sampling theorem while working for Bell Labs, and it has become one of the fundamental building blocks of digital technology. The theory states that, "A sampled waveform contains ALL the information without any dis tortions, when the sampling rate exceeds twice the highest frequency contained by the sampled waveform" [24]. For example, an audio signal with a bandwidth of 20 kHz would call for a sample rate of 40 kHz samples/second. Additionally, no signal great than half the sampling frequency may enter into the digital conversion process. If frequencies greater than one half the sample rate are allowed to enter the signal path, false frequencies could become audible. These false frequencies are referred to as alias f requencies, and can be heard as harmonic distortion.

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12 Quantization The other component of digital sampling represents amplitude (signal level). In order to store and manipulate digital audio, quantization is used to transform voltage levels of continuous a nalog signals. Voltage levels are transformed into binary digits (bits). It is the job of the converter to determine the correct voltage level of the analog signal, and output a set of analogous binary numbers. The binary numbers represent the originally s ampled voltage, and are grouped together as a word. The converter does this process during a sample interval, at which point the voltage level is momentarily held. The accuracy of this process is dependent on the word's bit length, and the design of the sy stem. Common binary word lengths for professional digital recording systems include 16 bit and 24 bit, although some systems can perform calculations at 32 and 64 bit resolution. Greater internal bit resolution corresponds to higher quality. This is due to the fact that errors mostly occur within the least significant bits. The least significant bits are the final and smallest numeric value in a digital word. Higher resolution produces a data stream nearly free from errors. Advantages of Digital Recordin g Digital recording has many advantages that differ from those achieved from analog recording. According to Stockham, a digital recording is "robust," if a recording contains a billion bits, and none are changed when the recording is played back, then the recording is exactly the same. While this may seem like a fairly simple concept, the same is not true for an analog recording; a reel of analog tape can decay over time, or the machine itself may be responsible for variations in the playback of the tape [4 ]. Another advantage to digital recording is high dynamic range; recording with a 16 digit system, it is possible to achieve dynamic ranges of 90 dB or higher.

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13 Additionally, digital recording produces negligible modulation noise, modulation noise is ofte n 4 or 5 dB or less. According to Stockham, digital recording produces very low levels of distortion; both conventional distortions and those due to digitization are very small, even when reaching maximum signal levels [4]. Digital recording is known for having a flat frequency response at all levels. There is no low frequency cutoff due to any digital processes. Additionally, full power bandwidth is possible with digital recording, in the words of Stockham; high frequency headroom is not an issue [4]. A common issue with analog recording is an effect known as "print through;" print through is due to storing tape for long periods of time, and essentially causes audio to be transferred from one layer of tape to the other. This effect is not possible with d igital recording, which reinforces Stockham's statement that digital recording is "robust." Similar to print through is an effect called "crosstalk," which is an effect where simultaneous channels "bleed" into each other, usually occurring in low frequency ranges. Because of this effect, similar instruments had to be grouped together on the tape. For example, a kick drum would occupy track 8, and a bass guitar would occupy track 9. With digital recording, crosstalk can only be generated by analog electronic s. Another common concern with analog recording is self erasure of audio at high frequencies at high levels; this phenomenon cannot occur with digital recording [4]. Disadvantages of Digital Recording According to Bob Katz, there is both good and bad dig ital equipment; bad digital equipment can sound "edgy," "dimensionless," "hard sounding," and even "unclear," whereas good digital technology aims to be transparent. Bad digital equipment produces

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14 distortions that increase "edginess" and "hardness" in a re cording. These unwanted effects could be due to a number of components in the digital signal chain including poor converters, sharp filters, low resolution, jitter, improper dither, and other factors that occur in the analog signal path. Katz warns that pl acing A/D and D/A converters inside one chassis can cause major problems, add in the other components needed such as motors and spinning heads, and there is potential along the signal path for digital distortions and other errors. While digital technology offers a cheap recording solution to many, some of these low end equipment manufactures are producing equipment that Katz would refer to as "bad digital." Katz concedes that digital technology has come a long way from the early multitrack recorders (MTRs), but that even now an "acceptable" to "very good" MTR is in the price range of $2000. Other factors that have increased the sound quality of digital recordings are higher sample rates and bit depths offered on even the most basic MTRs [5]. Most engineers a re aware of the common problems associated with digital recording, and the supposed "harshness" it adds to a recording. A common solution is using more analog equipment in the signal chain. There has been a resurgence of analog equipment including tube mic rophones, tube preamplifiers and outboard equipment such as compressors and equalizers. Analog equipment is often used to add "warmth" to a recording that would be otherwise impossible to gain from a purely digital recording. Katz warns that this is more o f a band aid than a cure, but these processes can create a sort of "fuzzy blanket" that covers up the unwanted edginess produced by a digital system. While digital recording has improved tremendously in sound quality, bad digital recording is due to two ma in factors; linear frequency response, which often reveals non

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15 linearities in other parts of the signal chain, and built in distortions in the A/D or D/A conversions [5]. The Analog and Digital Hybrid Studio In the early days of digital recording, issues such as poor word clocks, or bad A/D and D/A conversion kept many studios from making the jump from analog to digital. Many of these disadvantages have been overcome with better technology, which in turn has also made digital audio more affordable for the commercial recording studio and home studio engineer. Digital audio has certainly become more practical, whereas analog remains revered for its character. A hybrid studio is defined as a studio in which a DAW is the central component, where analog hardwar e and digital software interact together [12]. Commercial studios have operated in this fashion for many years. A typical set up would involve a DAW and a computer. Additionally the DAW would need A/D and D/A converters and a word clock. Most commercial fa cilities are centered around a large format analog console, which contain microphone preamplifiers, equalizers, and sometimes other processors such as compressors/limiters. Racks of outboard analog equipment often times occupy studios. This equipment along side the DAW gives the engineer the best of both worlds, analog fidelity and digital efficiency. This can be taken one step further, by integrating a tape machine into the signal chain. Eight, 16 or 24 track tape machines can be used for basic tracking of one or all instruments in a recording session. These tracks can then be recorded into a DAW, and further processed, edited, or added to with overdub recordings. The possibilities here are endless, as the engineer can mix completely "in the box" using the D AW and plug in processes, or "outside the box" using analog hardware. Another common technique is to use a combination of the two to

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16 achieve the finest possible results. Lastly, the engineer can bounce down using a two track tape machine before mastering t o further provide character to the recording. Analog Integration in the Project or Home Studio Modular Systems. With the rise of modular audio processing racks, project and home studios are able to easier incorporate analog equipment into their often time s smaller studio spaces. This means the budget and space conscious home studio owner can use much of the same professional quality analog equipment used in larger, professional facilities. Modular and standalone audio equipment has gained a tremendous amou nt of popularity. An article discussing "New Products for 1988" in an October 1987 issue of a popular trade magazine listed only three standalone microphone preamps. Today countless manufacturers produce standalone and mutli channel preamps and other outbo ard equipment. Additionally, various modular systems have gained popularity, most notably the API 500 series and their "Lunch Box" rack, as well as the Solid State Logic X Rack and Tonelux V Rack. Modular systems are compact, enabling them to be used in t he studio, or transported outside the studio for on location recording sessions. Another convenient feature of modular systems is that they feature all the input/output routing on the rear of the chassis, and only require one power supply for the entire ra ck. Modular systems are sometimes referred to as analog building blocks, enabling the engineer to create their own "lego studio." Another benefit of modular systems is they allow the engineer to build slowly, without having to pay all of the cost up front. An engineer can simply buy a microphone preamplifier, and chassis, and later add more preamplifiers, or an equalizer and compressor to build a channel strip. This alleviates some of the upfront cost that is required when buying a large format analog conso le.

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17 The Tonelux V Rack comes in two models, a 16 slot or 8 slot chassis. Modules can be placed in any order the user sees fit. Current modules include a microphone preamp, an equalizer, a compressor, and a plethora of other unique modules including stereo and surround mixing and aux modules, master output modules, monitor modules and even faders. The flexibility of this modular system allows a user to create channel strips, a summing amp, and even a fully functional stereo or surround console. Perhaps the only downside to the Tonelux V Rack is that modules and the chassis are currently only compatible with each other, and there are no third party manufacturers producing modules for this format [15]. Perhaps the most complex of the modular systems is the So lid State Logic (SSL) X Rack. The X Rack chassis can accommodate up to eight SSL modules. The available modules include several microphone preamplifiers and compressors, an equalizer, an eight input summing module, and a master bus module. The X Rack can b e configured as several SSL channel strips, a summing amp, or a collection of audio processing tools. What makes the X Rack unique from the other modular systems is their Total Recall feature, which enables the rack to recall exact settings on the modules. Each X Rack features a microprocessor for the Total Recall system to function, as well as the ability to store 32 recall settings. Total Recall settings can also be exported or imported through the MIDI interface on the back panel of the chassis. Addition ally, three X Racks can be connected to the Total Recall system of any SSL AWS900 series analog console using nine pin d sub connectors. A unique feature of the Total Recall system is the ability to copy settings from one module to another of the same type this feature is highly useful for modules acting as a stereo pair. The SSL X Rack is essentially modeled to act and

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18 sound like a miniature SSL console. This modular setup is ideal for an engineer without the ability to own a large format analog console, but looking to add classic SSL character into their recording or mixing chain. Much like the Tonelux system, SSL X Racks and modules are only compatible with each other [14]. The 500 series was originally developed and used strictly by API; this format pr ovided several modular units including a preamplifier, equalizers and compressors. API also produces a "Lunch Box" chassis, which can house and power up to six modules, as well as a ten slot chassis. Since 2007, third part manufacturers have begun making m odules and racks for the 500 series. API has since created the VPR Alliance, a standardized program for third party manufacturers to conform to when developing modules for the 500 series. The guidelines provide design specifications that ensure modules phy sically fit into the rack, as well as conform to the electronic standards of the API racks. The VPR Alliance also ensures each module is receiving the correct amount of power therefore no modules are underpowered. The 500 series is by far the most popular modular system on the market, with many third party manufacturers producing both racks and modules. Racks are being manufactured that can contain one or two modules, with larger racks holding as many as ten. Aside from having the option to use third party manufacturers modules, the 500 series is compact and portable. The API ten slot chassis only uses three rack mount spaces, can hold up to ten modules, and needs only one power supply. Using other stand alone rack equipment would require at least 16 rack sp aces, as well as multiple power supplies or IEC power cables. The startup cost of a rack and two preamplifiers is around the same price as a standalone two channel preamplifier, but in the long run buying more modules to fill the rack would most likely

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19 end up being cheaper than buying another standalone preamplifier or other effects processor. Innovations are even being made in the world of 500 series equipment; recently Aphex released a four slot 500 series rack that also doubles as a USB interface for a D AW. This chassis can house up to four modules, and features an additional S/PDIF input/output for two more channels of audio. Other features include studio monitor outputs, headphone outputs and MIDI connectivity. This piece of equipment truly shows the di rection the analog/digital hybrid studio is headed in [16]. Analog Integration in the Recording Process Perhaps the most straightforward method of incorporating analog character into a recording is during the tracking process. Even when working with a DA W, it is fairly simple to integrate analog devices into the signal chain. In the digital signal chain, the two most important components are the A/D, D/A converters and the word clock. The two most important pieces in the signal chain before reaching the A /D converter are the microphone, and the microphone preamplifier. There has been some rise in popularity towards "straight wire with gain" preamplifiers; these "clean" or "neutral" sounding preamplifiers are suitable for many types of instruments. Still th ough, there are plenty of options for preamplifiers that will give the source material a more colored sound. Although the technology has been in use since the early 1900's, vacuum tube equipment has remained popular and even sought after in professional re cording studios [17]. Tube microphones, preamplifiers, equalizers and compressors are all valuable equipment that can be integrated into the project studio. Tube electronics add a small amount of second harmonic distortion, which our ears often find deligh tful [22].

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20 Engineers also often talk about equipment with transformers. Transformers have played a crucial part in circuit design since the earliest days of analog audio equipment. It's fairly common to see transformers at the input, output and amplificat ion stages of analog equipment. Harmonic distortion occurs in transformers due to hysteresis (low level signals) and saturation (high level signals) [3]. Low frequencies are usually affected greater than mid to high frequencies. Hysteresis can cause quiete r signals to sound "richer" and "denser" due to the added harmonics. Because transformer based equipment has a slightly higher distortion ratio than transformerless equipment, it tends to produce a more colored sound [3]. Good quality transformers are expe nsive, which is one reason manufacturers have gone transformerless. Another reason for the decrease in transformer based preamps is they are not as necessary when working with solid state equipment. An input transformer is used to match the low output impe dance of a microphone to the high input impedance of a vacuum tube [22]. Output transformers provide a balanced output that will work well with any input, balanced or unbalanced. Exceptional sounding preamps exist that are both transformer based and transf ormerless. Although not always the case, transformer based preamps will add more coloration to the sound source. Another factor to consider is whether or not the microphone uses a transformer. A component often discussed in analog audio equipment is the o perational amplifier (op amp). An op amp is a type of amplifier that performs a mathematical operation. In a microphone preamp, it is responsible for multiplying the input voltage by the desired gain [22]. Vacuum tube op amps were created by Bell Labs and used frequently in the 1940's and through WWII. In the 1950's and 60's solid state op amps became a suitable replacement for tube op amps; tube op amps were bulky and consumed

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21 large amounts of power [23]. Integrated circuit (IC) op amps were developed in t he mid 1960's and continue to be improved on [18, 23]. Up until about 1977, most solid state amplifiers used discrete transistor Class A circuitry. 1977 saw the introduction of the TL072 and 5532 op amps, which we suitable for use in solid state preamplifi ers, and still remain popular choices in audio equipment. Some popular op amps used in microphone preamplifiers include the Jensen 990, the API 2520 and the Burr Brown PGA2500. Variations and clones of these op amps are often used in many beloved preamplif iers, and the Burr Brown PGA2500 has become popular in many DAW preamps as it offers digitally controlled gain [22]. The combination of quality microphones and quality microphone preamplifiers, as well as a good digital signal chain can lead to an excepti onal recording. Additionally, many engineers will incorporate analog equalizers and compressors into their recording signal chain. With a large format analog console, this can be done through the use of insert sends and returns. Many smaller project studio s can make use of outboard equipment through the use of a patch bay. These processes are normally done somewhat subtlety; a common example would be an engineer using an EQ to get rid of the ringing sound in a snare drum, or using a compressor to even out t he dynamic playing of a bassist. Of course these processes can also be done more extreme, often times an engineer will use a compressor on a drum room microphone to literally squash the dynamics. Other times, the engineer may choose not to use any additio nal processing, and they can certainly later add more analog character in the mixing and mastering phases. Analog tape can be taken advantage of in the tracking process, by either recording one instrument or all instruments to tape. A common use of analog tape in the modern

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22 hybrid studio is to track drums onto tape, and then record the output of the tape machine into the DAW. This gives the engineer the flexibility of digital, and the sound of analog. Additionally, other instruments can later be overdubbed into the DAW. Drums are commonly given this treatment as analog tape is known to give drums a desired low frequency boost, and can tame cymbals, making them sound more natural. Still though, some engineers rely on tape for the entire recording session, ch oosing to then record their analog tracks into their DAW of choice for mixing and editing. While to some this may seem like an extra step in the recording process, it gives the engineer the best of both worlds. Analog tape can also be used when bouncing do wn a mix for mastering. An engineer can sum their mix using either analog or digital means, and record this stereo mix onto either a "" or !" two track tape. This tape can then be sent to the mastering engineer. This is a quick, and cost effective way to i mpart analog character into a mix. Modern Examples of Analog Recording One of the more popular musicians advocating for analog use in recording is Dave Grohl and his band the Foo Fighters. Their 2011 album Wasting Light was recorded stric tly with analog tape. Although the Foo Fighters own a professional recording studio in Los Angeles, CA, Grohl chose to record the album at his home in Encino, CA. Grohl essentially brought in enough equipment to turn his garage and spare room located above the garage into a recording studio. This included two Studer A827 tape machines, an API 1608 analog desk, and a surplus of outboard analog equipment. Throughout the process Grohl insisted on not having a computer in the converted recording studio. Grohl a nd the Foo Fighters enlisted the help of producer Butch Vig (Nirvana, Smashing Pumpkins) and engineer James R Brown (Nine Inch Nails, The Killers) to record the album. Minimal

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23 acoustic treatment was done in the garage where the drums were recorded to achie ve a sort of unpolished and raw sound. It took roughly 13 weeks to record the album, and then Alan Moulder was brought in to mix the album. Mixing originally started at Chalice Studios in Hollywood, CA, but the majority of the mix was completed at Grohl's converted home studio. All the mixing was done from the analog tapes, and the only instance of digital equipment entering the signal chain was through the use of an Eventide digital reverb, Lexicon PCM42 delays and an Eventide Eclipse used for vocal doubli ng. Wasting Light was very well received upon its release, including winning a Grammy for Best Rock Album. Vig was quoted as saying, "people say it sounds honest, unlike anything they've heard lately" [27]. Another highly successful album recorded with analog tape is Tool's 2006 album 10,000 Days The album was recorded and mixed by Joe Barresi (Queens of the Stone Age, the Melvins) using Studer A827 tape machines and Ampex GP9 tape. The album was recorded into Pro Tools strictly to archive the recordin gs [6]. In 2005, Andrew Scheps engineered Stadium Arcadium the ninth full length album by the Red Hot Chili Peppers. A unique aspect of this album is the vinyl release; the album was recorded to two inch analog tape, mixed on an analog console to half in ch tape, and mastered in analog. Lastly, the album was cut to vinyl, keeping the entire signal chain analog [26]. While these are just a few examples of successful albums recorded using analog tape there are still plenty of other musicians and engineers us ing analog tape. Jack Shirley, who owns and operates the Atomic Garden, a studio based out of Palo Alto, CA uses an analog/digital hybrid approach for recording and mixing. Recording is done with a 2 inch tape machine, and then transferred into a DAW for e diting, archiving and to take

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24 advantage of some of the other benefits a DAW offers such as automation. Mixing is also done in the analog domain, using an analog mixer and other hardware, and half inch tape [10]. Quite possibly the most famous advocate of a nalog tape is Chicago based engineer Steve Albini. Albini has worked on over 2000 records, and is most famous for his work with Nirvana, the Pixies, Robert Plant and Jimmy Page. Albini has owned and operated Electrical Audio since 1997, a multi room record ing studio that features multiple analog tape machines and very few pieces of digital equipment. I have always done things with the analogue method, and I still think it's the best method. So I have no reason to change. I've had a long time to accumulate equipment and microphones and techniques, and I've never been in a situation where I've had to say 'No, I can't do that, because we're working on tape.' If there were problems that I could not solve on tape, I might be compelled to use computers, but I've never encountered such a problem [25]. Additionally, Albini feels that high resolution digital audio such as Direct Stream Digital (DSD) and the Super Audio CD (SACD) sound "ok" but still not as good as a well made vinyl record [25]. Albini refuses to s acrifice quality for convenience; and while Albini is somewhat of a rare breed, his dedication to analog tape proves that not all engineers are sold on the quality of digital recording. Analog Integration in the Mixing and Mastering Process Analog equipme nt can easily be integrated into the mixing and mastering processes, even if the engineer plans to mix mostly in their DAW. For a project studio looking to add analog character in their mixes, an interface with plenty of analog outputs

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25 and inputs is essent ial. A patch bay can also be used to give the engineer more flexibility with their routing options. Analog equalizers, compressors, limiters and other outboard effects come in many different varieties; tube, solid state, mono, stereo, etc. For a project s tudio with a more limited budget, it's important to consider the price of equipment, but also how versatile the equipment is. A few factors to consider are will this piece of equipment work well with multiple genres of music? Is this piece of equipment bes t suited for only certain instruments, or will I be able to use it on many instruments? Is this piece of equipment mono, and if so, will I need a stereo pair? Professional mastering studios rely heavily on analog equipment for their signal processing. Whil e the majority of audio is sent to the mastering engineer as a digital audio file, the mastering engineer will generally use a combination of analog equalizers, compressors, limiters and other highly specialized equipment. A mastering engineer generally pe rforms the duty of mastering as their equipment is more suited for the task, and their studios are often acoustically treated in a different manner than that of a recording studio. Analog Summing Versus Digital Summing. In the days of analog tape, and eve n early on in the existence of digital recording, a mixed album or track was "summed" on a large format analog console. The channel signals were essentially mixed together at the group or main stereo busses. While some still work in this fashion, as digita l technology has improved and become extremely popular and convenient, most summing is now done in the digital realm. With digital summing, mixing occurs in the DAW, or "in the box," with the final mix being bounced down or printed to a single mono, stereo or multi channel

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26 audio file. A fixed length sample is created to represent the mixed tracks. For early digital recording systems and consoles, this task sometimes proved to be too much due to rounding errors and other complications. Large track counts co rrespond to a large number of signal samples being added together, which creates complex binary numbers. As digital technology improved, the issues associated with digital summing disappeared. Although there are problems associated with analog summing, som e engineers still prefer it to digital summing. Perhaps these engineers enjoy being able to physically touch faders or knobs as opposed to mixing in a DAW. Most problems associated with analog summing are due to inferior analog hardware that simply doesn't have the necessary headroom. While it makes sense for a home studio to sum in the digital domain, manufacturers have begun producing analog summing boxes with the space conscious engineer in mind. Manufacturers such as Dangerous, Rupert Neve and Tonelux h ave popularized analog summing boxes which often consume as little as one to two rack spaces. These summing boxes allow the engineer to send their outputs from their DAW into the summing box, mix their signals with physical knobs or faders, and then send t he stereo signal back into their DAW or to a two track tape machine. While these units take up less space than a large format analog console, the number of inputs, usually either eight or 16, often limits them. Limited inputs means the engineer usually nee ds to premix some of their tracks in their DAW, or buy and link together multiple summing boxes. While there are advantages and disadvantages to analog summing, it's often overplayed that it will make a mix sound better. In reality neither method will make or break a mix. There are plenty of world famous engineers who use digitally summing, such as Dave

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27 Pensado, Charles Dye, and many others; likewise, there are plenty of engineers who still prefer analog summing. Mixing In The Box Versus Out Of The Box Possibly the greatest advantage to mixing in a DAW is being able to recall settings. This gives an engineer the ability to save a session, come back to it at a later date, and pick up right where they left off. It also gives the engineer the ability to wor k on the session at nearly any studio, assuming of course they have compatible software. While the quality of digital plug ins has improved tremendously, mixing with a DAW also gives the engineer the ability to use automation. Control surfaces have become quite popular with the rise of digital audio. A control surface gives the engineer the ability to automate mix settings such as volume levels, panning, mutes, and even plug in settings. Some manufacturers have popularized hybrid consoles, which feature ana log processing such as preamplifiers and equalizers, but also offer the ability to act as a control surface for a DAW. Perhaps one of the most exciting elements of mixing in a DAW is the nearly unlimited options the engineer has when it comes to plug ins. Although the quality of plug ins can vary, even some of the most renowned plug ins are often times cheaper than their analog counterparts. Mixing in the box also doesn't require a patch bay or patch cables, or the need for a large format analog console. Th e need for an interface with plenty of digital to analog conversion is also unnecessary if the engineer plans to mix solely in the box, and it's possible to mix with a simple USB or Firewire interface. One factor that must be considered when looking to m ix in the box is computer specifications. Higher track counts and more instances of plug ins require a computer with plenty of RAM, and powerful CPU's. Typically, a computer with stock

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28 specifications will not cut it for an engineer planning to do a lot of recording or mixing in the box. While advances in technology such as CPU hyper threading are making this less of an issue, the specifications of a computer should be carefully considered by an engineer planning to mix or record in the box. According to A ndrew Scheps (U2, Michael Jackson, Iggy Pop) "Many of the same mistakes can be made in analogue and in digital, the only difference is that they're more easily made in the digital domain" [26]. Scheps uses a hybrid approach to mixing that is quite practica l. Scheps starts mixing by using Pro Tools for a number of mixing tasks, which he considers "structural moves," these tasks, include submixing instruments. For example, all the drum tracks will be combined to occupy roughly 10 faders on his analog mixing d esk. Scheps considers this "prep work" an essential step in his mixing process. After he has all the tracks laid out across his two Neve 8086 analog desks, he begins moving faders and inserting analog hardware. For Scheps, the main reason for working in th e analog domain is being able to physically touch knobs and faders, instead of hunting around for something on a computer screen. Because Scheps mostly works out of his personal studio, his workflow is very similar from project to project, enabling him to quickly make adjustments. His Neve desks also feature flying faders, which allows him to use automation. While Scheps has an entire wall of analog hardware, he does use the occasional plug in. Scheps feels that digital recording is more forgiving whereas, "Analogue colours the hell out of the sound, and this can be an amazing thing, but you have to know what you're doing. You have to be aware of the gain structure, the noise floor, all these things that you don't really have to worry about the same way with

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29 digital." Not only does this method of mixing offer a more hands on approach, it gives a unique sound that is harder to replicate in the digital domain [26]. While some analog hardware aims to be completely transparent, other pieces of equipment are said to sound warmer, punchier, and fuller due to harmonic distortion provided by the circuit path. The downside to using analog equipment is the extensive documentation required to recall settings at a later date. Analog equipment also requires an interface ca pable of outputting multiple channels of analog audio, as well as other signal flow considerations. For the project studio owner, most choose to work in the digital domain, but it is fairly easy to incorporate a few pieces of analog equipment into the sign al chain. A project studio owner should choose equipment that suits their mixing needs, as there are plenty of affordable options to choose from.

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30 CHAPTER II METHODS Purpose of the Study This study was conducted to determine if analog tape plu g in or hardware emulation could accurately mimic a true analog tape recording. Further, this study was conducted to determine what elements can and cannot be emulated by analog tape plug ins or hardware emulation. Overview To conduct this study, an acous tic drum kit was recorded simultaneously to analog tape and a DAW (Pro Tools HD). The Euphonix CS200OP console allows options to split an audio signal through the use of its busses. Upon amplifying the microphone inputs with their perspective preamplifiers the signals were then split into the MTR 90 and A/D converter. This allowed for a completely separate analog and digital recording of the same performance. Drums were recorded onto analog tape due to the nature of the instrument; drums are more transien t than the other instruments involved in this recording. The style of music for this project is rock. Analog Tape/Pro Tools Specifications All audio recorded in Pro Tools was recorded at 24 bit, 96 kHz. Dan Lavry of Lavry Engineering Inc. argues there is an optimal sample rate, and recording above the optimal sample rate compromises the accuracy of audio. Lavry believes it is good practice to record the signals that are needed, while keeping everything else out (energy

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31 outside the human range of hearing). Lavry concedes we should accommodate the most sensitive ears, and allow a "safety margin" of 10 kHz. According to this theory, the optimal sample rates are 88.2 or 96 kHz. Ultrasonic frequencies describe sound waves with a frequency above the upper limit o f human hearing [13]. Capturing ultrasonic frequencies can potentially cause unwanted audible alterations due to non linearity in equipment. Non linearity causes a distortion called intermodulation, which is rather unpleasant to the human ear as a result o f this distortion being non harmonic. "Harmonic distortion tends to alters the timbre, it colors the sound' by changing the relative harmonic content" [13]. Intermodulation is much more offensive to the human ear, as it is not related to the sound or its harmonics. Linearity is worse in the ultrasonic frequency range, and therefore better in the audible range (lower frequency ranges). The simple solution is to avoid recording ultrasonic frequencies because the "spill over" could cause unwanted intermodula tion. Another reason to avoid sample rates higher than 88.2 or 96 kHz is that most microphones are designed to mimic the human hearing range; therefore recording above the frequency range of a microphone will not positively affect a recording. According to Lavry, at best ultrasonic frequencies will cause no harm to a recording, but they will also not help a recording in any way. A recording at 96 kHz has a theoretical bandwidth of 48 kHz, while the converters available today give a bandwidth of approximatel y 40 kHz. 2" ATR Magnetics Master Tape was used for this recording. ATR Magnetics is currently the only analog tape manufacturer in the United States, and their tape is known for low noise, high output and high resolution [11]. A speed of 30 IPS was used for this recording, while both 15 IPS and 30 IPS are considered "professional" speeds; each has

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32 their own distinct advantages. Many claim that 15 IPS has a better bass response, and there are also claims that 30 IPS has a better high frequency response an d a flatter overall frequency response. It's also believed that 15 IPS produces more noise than 30 IPS, but that can also depend on the machine, and how many tracks are being recorded (16 tracks vs. 24 tracks). The Otari MTR 90 was calibrated at +9 for thi s recording. Tracking Procedures Basic tracking was conducted over the course of two days, July 15 th and 16 th 2013 at Colorado Sound Studio. The drumset was placed in the larger of the two live rooms. The drummer did not play to a click track, and instead we opted to set up a headphone mix where the other musicians could play along with the drummer and provide scratch tracks. Two dynamic microphones were used on the kick drum; an Audix D6 was placed roughly six inches inside the shell of the drum aimed at the beater pedal. The other microphone used on the kick drum was a Yamaha SKRM 100 Subkick; this was placed outside of the drum shell, slightly off axis of the beater pedal. API 512c preamps were used for both kick drum microphones. Additionally, an Empir ical Labs EL8X Distressor was used on the Audix D6 to add compression, as well as a GML 8200 to add EQ.

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33 Figure I .1 Kick Drum Microphone Placement Figure I.2 Kick Drum Microphone (Inside Drum Shell) Close Up

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34 Two microphones were used on the snare drum, one condenser and one dynamic. An Audix i5 (dynamic) was used on the top head of the drum, roughly an inch to an inch and a half away from the rim, angled down at the drumhead. A Neumann KM86 (condenser) was used on the bottom head of the snare. This micr ophone was used in the cardioid pattern, about an inch away from the drumhead. API 512c preamps were used for both snare microphones. Additionally, an Empirical Labs EL8X Distressor was used to add compression, and a GML 8200 was used to add EQ on the Audi x i5 microphone (top drumhead). Figure I .3 Snare Drum Microphone Placement (Bottom)

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35 Figure I .4 Snare Drum Microphone Placement (Top)

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36 The drum set featured three toms, a floor tom and two rack toms (small and large). Three Sennheiser 421's were used to record the top drumhead of the toms, whereas three Shure SM57's were used to record the bottom drumhead. The Sennheiser 421's were placed roughly an inch or so away from the rim, angled down at the drumhead. The Shure SM57's were placed roughly at the center of the drumhead, about an inch away from the head. API 512c preamps were used for the top drumhead microphones, whereas the preamps from the Euphonix CA200OP were used for the bottom drumhead microphones. No compression or EQ was used on the to m microphones Figure I.5 Tom Microphone Placement Angle 1 (Top)

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37 Figure I.6 Floor Tom Microphone Placement Close Up (Top) Figure I.7 Floor Tom Microphone Placement Close Up (Bottom)

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38 Figure I.8 Large Rack Tom Microphone Placement Close Up (Top) Fi gure I.9 Small Rack Tom Microphone Placement Close Up (Top)

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39 Figure I.10 Small Rack Tom Microphone Placement Close Up (Bottom) Figure I.11 Large Rack Tom Microphone Placement Close Up (Bottom)

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40 Figure I.12 Tom Microphone Placement Angle 2 (Top)

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41 Several microphones were used for overhead and room microphones. A spaced pair of Neumann U87's was used as a stereo left and right overhead. Both microphones were used in the cardioid position, placed roughly four to five feet above the drum kit. A center overhead was also used, and for this I chose to use the Royer R 122, a phantom powered ribbon microphone. This microphone was placed over the center of the drum kit, roughly four to five feet above the drum set. Three microphones were also used as room microphones. Two AKG C414's were used as far left and far right room microphones, in the figure eight pattern. These microphones were placed roughly 15 feet away from the drum set, roughly six feet off the ground. A center room microphone was also us ed, and for this I chose to use a Neumann 147 tube condenser. This was placed roughly 10 feet away from the drum set, aligned with the kick drum. This microphone was roughly six feet off the ground. Brent Averill 1073 preamps were used on the Neumann U87 o verheads, Neve 1073 preamps were used on the AKG C414 room microphones, and Vintech X81 preamps were used on the center room microphone (Neumann 147) and center overhead microphone (Royer R 122). Additionally, a Smart Research C2 stereo compressor was used on the Neumann U87 overheads. A Tube Tech LCA2A stereo compressor was used on the AKG C414 room microphones, and a Urei 1176LN compressor/limiter was used on the Neumann 147 microphone. No EQ or other processors were used on these microphones.

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42 Figure I .13 Drum Kit Overhead Microphone Placement Angle 1 Figure I .14 Drum Kit Overhead Microphone Placement Angle 2

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43 An AKG C451B was used on the hi hat. This cardioid condenser microphone was placed roughly 6 inches above the hi hat. A preamp from the Euphoni x CA200OP was used, and no additional processing was applied to this microphone. Figure I.15 Hi Hat Microphone Placement

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44 Figure I.16 Tube Tech LCA2A Settings (Channel 1) Figure I.17 Tube Tech LCA2A Settings (Channel 2) Figure I.18 Smart Resear ch C2 Settings

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45 Figure I.19 Empirical Labs EL8X Distressor Settings Figure I.20 Empirical Labs EL8X Distressor Settings

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46 Figure I.21 Urei 1176 LN Settings (*only top unit used) Figure I.22 Urei 1176 LN Settings

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47 Figure I.23 GML 8200 EQ Settings Le ft Channel Angle 1 (Kick, In) Figure 1.24 GML 8200 EQ Settings Left Channel Angle 2 (Kick, In)

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48 Figure 1.25 GML 8200 EQ Settings Right Channel Angle 1 (Snare Top) Figure 1.26 GML 8200 EQ Settings Right Channel Angle 2 (Snare Top)

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49 Figure I.27 DAW Int erfaces Figure I.28 Otari MTR 90 24 Track Analog Tape Machine

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50 Table I.1 Equipment Used at Colorado Sound (7/15 7/16) Manufacturer Model Number Used Use Other Info. Audix D6 1 Kick Drum, In Dynamic Microphone Yamaha SKRM 100 Subkick 1 Kick Drum, Out Dy namic Micorpohne Audix i5 1 Snare Drum, Top Dynamic Microphone Neumann KM86 1 Snare Drum, Bottom Condenser Microphone Sennheiser MD421 3 Floor and Rack Toms, Top Dynamic Microphones Shure SM57 3 Floor and Rack Toms, Bottom Dynamic Microphones AKG C45 1B 1 Hi Hat Condenser Microphone Neumann U87 2 Overhead, Left and Right Condenser Microphones AKG C414 2 Room, Left and Right Condenser Microphones Neumann 147 1 Room, Center Tube Condenser Microphone Royer R 122 1 Overhead, Center Ribbon Microphone API 512C 6 Kick (D6 & Subkick), Snare (i5 & KM86), Toms (Floor and Rack Toms, Top) Microphone Preamplifiers Neve 1073 2 AKG C414's Microphone Preamplifiers Vintech X81 2 Neumann 147, Royer R 122 Microphone Preamplifiers Brent Averill 1073 2 Neumann U 87's Microphone Preamplifiers GML 8200 1 Kick (D6), Snare (i5) Stereo Equalizer Urei 1176LN 1 Neumann 147 Compressor / Limiter Tube Tech LCA2A 1 AKG C414's Stereo Compressor Smart Research C2 1 Neumann U87's Stereo Compressor Empirical Labs EL8X 2 Kick (D6), Snare (i5) Compressor Apple Mac Pro 1 Digital Recording Computer Avid Pro Tools 10 1 Digital Recording DAW Software Avid/Digidesign 192 I/O 4 A/D Conversion, D/A Conversion, Word Clock, etc. DAW Interfaces Otari MTR 90 1 Tape Recording 24 Track Analog Tape Machine

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51 Table I.1 Equipment Used at Colorado Sound (7/15 7/16) Continued Analog Tape Emulation With a resurgence in popularity, many manufacturers have taken to creating analog tape plug ins, and a few have even created analog tape hardware devices. Some of the more popular plug ins includes the Eddie Kramer Master Tape from Waves, Slate Digital Virtual Tape Machines, Universal Audio Ampex ATR 102 Mastering Tape Recorder and Studer A800 Multichannel Tape Recorder. There are countless other plug ins, with some ra nging from being more of a novelty, to others getting close to being an exact replication of tape. Rupert Neve Designs were one of the first to create an analog hardware replication of a tape machine with their 5042 and 542 pieces of equipment. Other hardw are manufacturers include Crane Song and their Hedd 192, as well as Anamod and their ATS 1. These pieces of equipment and plug ins all aim at giving the engineer the unique sound of tape, without the hassles associated with tape. The question becomes, if t hese plug ins and hardware devices can accurately emulate analog tape, is there still a use for analog tape in the professional or project studio? Slate Digital Virtual Tape Machines Plug In. Slate Digital and head algorithm developer Fabrice Gabriel crea ted their Virtual Tape Machines (VTM) plug in after more than a year of research. The goal was to create the most authentic replication of an analog Manufacturer Model Number Used Use Other Info. Euphonix CA200OP 1 Microphone Preamplifiers used on Toms Bottom (SM57's), Hi Hat (C451) Used for splitting signa l between DAW and tape machine Digitally Controlled Analog Console

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52 tape machine in a digital plug in format. The plug in can be used as a 2 inch, 16 track tape deck, or !" 2 track tape deck. According to Steven Slate, the creator of Slate Digital, "Your mixes will come to life. Things will be easier to balance. Tracks will need less EQ and compression. Depth, space, and warmth will be achieved like you've never heard before". The 2 inch 16 track is based off the famous Studer A827 with 16 track headstock from NRG Recording Studios. This specific tape machine has been used on countless best selling albums, and is a great tracking machine. The sound of this machine can be chara cterized as having a "Fat, punchy, thick sound with a very detailed top end". The !" 2 track is based off the Studer A80 RC with !" headstock from Howie Weinberg Mastering. The sound of this machine can be characterized as having "A thick low end, nice mid range, and a smooth top that perfectly takes away the digital edge in the most natural way". Additionally, the plug in was modeled after two formulations of tape, the more classic 456, and the more modern GP9. 456 tapes began being produced in 1975 and we re marketed as a "high output" tape, which enabled the tape to handle higher headroom available by the new tape machines being produced at the same time. 456 is a "+6" tape, which basically gives you an additional 6dB of headroom before any tape saturation occurs. GP9 tape was produced much later, and was known as "+9" tape; this tape became very popular due to the fact that you could record at higher levels without the artifacts associated with tape such as saturation and distortion. These two tapes have d ifferent qualities, the 456 is characterized as being more colorful, while GP9 is known for being more "punchy" due to the fact it has more headroom.

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53 While a lot of detail went into replicating the tape formulations, there was also a lot of care given to the specifics of the tape machines such as tape speeds, bias, noise reduction, and wow and flutter. VTM can be used at two different tape speeds, 15ips (inches per second) and 30ips. 30ips is known for having less noise, flatter frequency response, and an extended high end. Steven Slate recommends this speed "For a pristine sounding high end with smooth saturation on peaks, and a nice thickening of the upper low end." 15ips is often known for sounding "fatter" but it also has a higher noise floor. The mid r ange of 15ips is also slightly extended giving this speed more mid range presence, or "bite." Bias can also be manually adjusted, or used in the "normal" setting. There are also two additional bias settings, one above and one below the recommended bias va lues. With bias set to high, high frequencies saturate earlier, and when set to low, high frequencies will saturate later with increased dynamics. Additionally, VTM is packed full of extra features such as noise reduction and hiss automute, which automatic ally mutes tape hiss when no signal is present. Noise reduction defaults to 3dB, but when using VTM on multiple tracks of a mix, the hiss can become overwhelming. The noise reduction feature was built in to give the ability to reduce the amount of tape hi ss. One of the other interesting features built into VTM is Wow and Flutter, and is intended to emulate subtle pitch and amplitude variations inherent in a real tape machine. This setting can be adjusted from 0% (off) to 100%, with Steven Slate claiming m ost carefully maintained machines being around the 25% setting. Calibration levels can also be user defined, which can give the user more saturation, and better signal to noise ratio, or less saturation and more noise. The recommended signal chain when mix ing is using

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54 the 2 inch, 16 track VTM as the first plug in on all tracks, and then using eq, etc, with the !" two track on the master bus. Rupert Neve Designs 5042/542. The Rupert Neve Designs (RND) 5042 is part of their Portico series, and is a "true ta pe" emulator and line driver. While there is no tape used in the unit, "The Portico 5042 incorporates an actual tape drive circuit that feeds a tiny magnetic head' which, in turn, is coupled to a correctly equalized, replay amplifier" [21]. The design of this non linear circuit offers the user the ability to add low frequency distortion (mostly third harmonic), as well as a boost to around 300 Hz [20]. These effects are similar to what even the most well maintained tape machines produce. The unit can also be bypassed, and used as a line driver. This simulates a technique in which an engineer will pass audio through a tape machine without actually recording to tape. This can help the engineer capture the sound of the electronics used in the tape machine and add a desired fullness to their recording [20, 21]. The 5042 was originally released as a half rack unit with included power supply and input/output routing on the back of the unit. The 542 recently debuted as a 500 series module, and uses many of the sa me features as the 5042. The 5042 has the ability to switch between two tape speeds, 7.5 IPS or 15 IPS, each tape speed affects the sound source differently. One review of the unit described the 7.5 IPS setting as "chunkier and duller" whereas the 15 IPS s etting was "tighter and clearer." With the 15 IPS setting used on a kick drum, the reviews found the kick drum to sound fuller and have an added low end presence. When used on cymbals, it tended to reduce edginess and make them sound more polished and natu ral. There was also a consensus that it reduced sibilance on vocal tracks [20, 21].

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55 Aside from tape speed, the 5042 offers the ability to control the amount of record level, essentially the amount of tape saturation. When the input level is increased, the output level is simultaneously decreased. The circuitry of the 5042 adds coloration to the sound source; even with the saturation control turned completely anti clockwise, a slight coloration can be heard. Correct gain structure is important when using th e 5042, as the input signal level will affect the amount of coloration. Turning the saturation control up will increase harmonic distortion and transient compression. This can be done subtlety, or more extreme to produce an overdriven and saturated sound. This effect is meant to mimic driving an analog tape machine [20, 21]. Overall the consensus of the 5042 is that it very closely mimics a real analog tape machine. It can help "smooth over" a recording and make a digital recording sound less linear or ste rile. It can also add extra low frequency "weight" and "fullness" while remaining dynamic. The 5042 is very simple, easy to use, and only requires half a rack space for a two channel module. Perhaps the only downside to the 5042 is there are limited meters and the unit is not based off any particular tape machine, rather it is meant to emulate the general effects produced by one [20, 21]. Post Tracking Procedures Upon completion of all tracking, the output of the MTR 90 tape machine was routed into new t racks in Pro Tools. This audio was recorded at 24 bit, 96 kHz into the same session as the digital drum recording. Once the tracks were time aligned, a duplicate of all the raw, unprocessed digital tracks was made. One set of digital drum tracks was left u nprocessed, while the other set had the Slate Digital VTM plug in applied to each track. Lastly, the unprocessed digital tracks were routed through the Rupert Neve Designs

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56 5042 tape emulator, with the output recorded back into Pro Tools. This gave me four different versions of the same recording; the original digital recording, the original analog tape recording, the digital recording with VTM applied, and the digital recording processed by the 5042. Settings varied on the RND 5042; some drums required mo re saturation than others to sound like their analog equivalent. Settings on the VTM plug in were roughly the same on each track, with slight input and output levels being fine tuned as needed. Slight level (volume) adjustments were also needed in order fo r all tracks to have roughly the same overall level. This was an important step; a perceived level difference could unintentionally persuade the listener into thinking the louder version sounds better. Table I.2 Equipment List For Tape Emulation Manufact urer Model Use Other Info. Rupert Neve Designs 5042 Hardware Tape Emulation 2 Channel Tape Emulator Avid/Digidesign 192 I/O A/D Conversion, D/A Conversion, Word Clock, etc. DAW Interfaces Avid Pro Tools 10 All audio processing tasks DAW Software Apple Mac Pro Pro Tools Computer Slate Digital Virtual Tape Machines Software Tape Emulation DAW Plug In

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57 Figure II .1 5042 Emulation on Kick Drum (Audix D6) Figure II.2 5042 Emulation on Kick Drum (Yamaha Subkick)

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58 Figure II.3 5042 Emulation on Snare Dru m (Audix i5) Figure II.4 5042 Emulation on Snare Drum (Neumann KM86)

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59 Figure II .5 5042 Emulation on Floor Tom and Small Rack Tom (Sennheiser 421) Figure II.6 5042 Emulation on Large Rack Tom (Sennheiser 421)

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60 Figure II.7 5042 Emulation on Hi Hat and Center Room Microphone (Neumann 147) Figure II.8 5042 Emulation on Left Room Microphone (AKG C414)

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61 Figure II .9 5042 Emulation on Right Room Microphone (AKG C414) Figure II .10 5042 Emulation on Left Overhead Microphone (Neumann U87)

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62 Figure II .11 504 2 Emulation on Right Overhead Microphone (Neumann U87)

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63 Figure II.12 Slate Digital Virtual Tape Machines Settings Figure 11.13 Slate Digital Virtual Tape Machines Calibration Settings

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64 CHAPTER III RESULTS Through this study I have determined there are some aspects of analog tape that are possible to recreate through the use of analog hardware and digital plug ins. Digital recording offers a flat frequency response at all frequencies, whereas with analog recording, the combination of tape mach ine and tape speed will affect certain frequencies. This is most evident in the low frequency ranges, with most machines giving a slight boost to bass frequencies. This is one of the reasons people claim that drums recorded to analog tape sound "bigger" or "fuller." For this study, I believe this is the easiest factor to recreate, especially with the analog hardware unit (RND 5042). The RND 5042 did bring fullness to the kick drum that it seemed to be lacking in the digital recording. Tape saturation is a nother effect many seek when recording to analog tape. I feel this aspect is possible to achieve to some extent. Tape saturation is essentially a form of compression. With tape saturation, transients are essentially rounded off, the harder the tape is push ed, and the earlier the distortion will start to occur. With digital recording, if there is not adequate headroom, the signal will clip. Digital audio is less forgiving in this aspect. The Slate Digital VTM plug in allows the user to adjust how much tape s aturation they want. Similarly, the RND 5042 has a saturation adjustment control. I feel both of these units performed this function fairly well. This recording did not feature any extreme examples of tape saturation, and it is possible neither of the unit s would accurately replicate a more severe example of tape saturation. I believe the VTM and RND 5042 added an acceptable level of saturation, especially on the snare tracks.

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65 While the Slate Digital VTM plug in is modeled after two somewhat famous analog tape machines through the use of algorithms and programming, the Rupert Neve Designs 5042 is modeled after the electronics of a tape machine. The advantage to using the RND 5042 is that the audio is actually being passed through an analog signal chain, wi th real analog components affecting the sound. This means actual harmonic distortion is being applied to the audio, just as it would be if it were passing through an analog tape machine's electronics. I feel this is an advantage to the RND 5042, and create s a more accurate tape sound. I feel both processors made the drum overhead and room microphones sound fairly close to the analog tape recording, and made them sound a bit more natural. "Wow" and "flutter" are two other components needed to consider when discussing an analog tape recording. Although several plug ins have a Wow and Flutter control, many claim this is not possible to replicate through emulation plug ins. I feel this is the hardest aspect to judge, and extremely dependent on the machine. Ove rall I don't think it is entirely possible to recreate this phenomenon with a plug in. Although the Slate Digital VTM plug in does attempt to create this effect, and give the user a range of settings they can adjust, the RND 5042 does not offer this settin g, and therefore is more accurate in that sense. The bottom line with analog tape is there are always going to be several factors at play that affect the recorded sound; the way in which the tape machine was biased, the amount of "wow" and "flutter," the type of tape used, etc. These factors are perhaps too much to neatly program into a plug in emulator, or analog hardware unit. While both of the processors examined in this study aim to replicate analog tape, it may be impossible

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66 to exactly replicate an a nalog tape machine because of all the variables involved. What these processors do succeed at accomplishing is adding analog character to a recording. The RND 5042 does this through an analog circuit, whereas the Slate Digital VTM plug in models an analog tape machine through complex algorithms. To the experienced engineer that remains faithful to analog tape, these processors may not achieve what the engineer is looking for when it comes to an analog recording. Those who can take advantage of this technol ogy are project studio engineers who either do not have the space or the budget to incorporate a real analog tape machine into their studio. While neither of these processors, or perhaps any analog tape emulator will give the engineer the results of a real analog tape machine, they will certainly get them close. They can also be used to improve the quality of a recording, and make a digital recording sound less pristine if that is their goal. While the RND 5042 may seem like quite an expense for a project s tudio owner, the Slate Digital VTM plug in is more moderately priced, and will achieve similar results. Through the use of this technology, as well as a good analog and digital signal chain, project studio recordings can sound closer than ever to the recor dings being produced by a professional recording studio. In general, the characteristics that engineers want to emulate from a tape machine are tape saturation, frequency response, and 3 rd harmonic distortion. Through the use of VTM or RND 5042, one can co me very close to reproducing these qualities in a digital recording. Overall I preferred the RND 5042 and felt it more accurately emulated the analog tape recording. While the VTM plug in was very close as far as quality, its ease of use and cheaper price tag make it an exception plug in for any project studio engineer to own.

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67 CHAPTER IV CONCLUSIONS Other Factors To Consider There are many factors that could be changed in order to produce different results with this study. The type of tape machine, cali bration settings, and type of tape used, and how much tape saturation occurs could all make these results vary. Otari tape machines are known for being fairly neutral tape machines, whereas other manufacturers such as Studer and Sony/MCI are known for havi ng more character. Similarly, some engineers claim 16 track machines perform better than 24 track machines. The way in which the machine was calibrated can also be a huge factor. A machine calibrated at +9 has an additional 9 dB of headroom before tape sat uration and distortion starts to occur, whereas a machine calibrated at +3 only has an additional 3 dB of headroom. While this study was only conducted with an acoustic drumset, the same methods could be applied to any instrument. Additionally, the genre of music used for this study was rock, and other genres could be tested as well. Perhaps it would be inappropriate to apply this study to a classical recording, but there are several genres that can benefit from analog recording. Final Thoughts Digital audio has improved remarkably since its inception, and early shortcomings have improved over time. Although professional grade digital audio equipment remains costly, even the quality of cheaper digital audio equipment is improving. With the rise of digita l audio in home and project studios, the signal chain is often an afterthought to some engineers. While it is certainly possible to acquire a simple

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68 DAW setup involving a USB or Firewire interface and a computer, the results will hardly be close to profess ional grade without considering the other elements in the signal chain. The quality of the built in preamplifiers in many DAW interfaces is often subpar, and cramming too many elements (A/D, D/A converters, word clock, etc.) into one rack enclosure can oft en lead to compromises of quality. Modular systems have given the project studio the ability to incorporate analog hardware into their signal chain, without having to purchase a large format analog console. Other equipment such as analog summing boxes allo w for an easy and convenient method for analog mixing. While it is getting harder and harder to argue against the quality of digital recording, both the analog and digital signal chains are important to consider when setting up a project studio; one weak l ink can compromise the quality of a recording. Only a few of the elements needed to construct a professional grade project studio are considered in this portfolio; other elements such as acoustic treatment and monitoring are not considered but are quite po ssibly just as important. Although many have made the switch from analog to digital, some engineers and musicians remain faithful to analog technology and recording. This leads to an interesting discussion, as to whether or not the qualities associated with analog tape can be reproduced through the use of analog hardware emulation or digital plug in emulation. Through this portfolio I have found that some of the desired qualities can be achieved through the use of analog hardware and plug in emulation. W hile only one plug in and one hardware emulator were tested, these two emulators show the direction the industry is headed towards, and improvement on these designs is imminent.

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69 The goal of this portfolio is not to determine which recording medium produc es a higher quality recording, but rather to determine if recording technology is at the point where digital recording can produce similar results to an analog recording. I feel through the use of a hybrid recording setup, many of the desired results of an alog recording can be achieved through the use of digital recording, and analog tape emulation. The music industry is shifting towards digitally released albums and singles, and the majority of listeners are using subpar playback systems or mobile devices. Although this is a discouraging trend, we as engineers should always strive to produce the highest quality recordings, regardless of how the listeners intend to playback the recording.

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70 REFERENCES 1. Schoenherr, S. (2005, July 06). Recording technology history Retrieved from http://www.aes.org/aeshc/docs/recording.technology.history/notes.html 2. Huber, D., & Runstein, R. (2005). Modern recording techniques (6th Ed. ed., pp. 187 298). Burlington, MA: Focal Press. 3. Robjohns, H. (2010, F ebruary). Analog warmth the sound of tubes, tape & transformers Sound on Sound Retrieved from http://www.soundonsound.com/sos/feb10/articles/analoguewarmth.htm 4. Stockham, T. (1982). The promise of digital audio. Journal of the Audio Engineering Socie ty Retrieved from http://www.aes.org/e lib/browse.cfm?elib=3419 5. Katz, B The pros and cons of recording and mixing via analog versus digital Retrieved from http://www.digido.com/articles and demos12/13 bob katz/27 back to analog.html 6. Forlenza, J (2006, July 01). The making of tool's "10,000 days" Retrieved from http://mixonline.com/recording/projects/audio_making_tools_days/ 7. Robjohns, H. (1998, August). All about digital audio, part 4. Sound on Sound Retrieved from http://www.soundonsoun d.com/sos/aug98/articles/digitalbasics.html 8. Ryan, K., & Kehew, B. (2006). Recording the beatles (p. 230). Houston, TX: Curvebender Publishing. 9. Vig, B. (2009, June) 1993 smashing pumpkins siamese dream [Online forum comment]. Retrieved from http ://www.gearslutz.com/board/q butch vig/398145 1993 smashing pumpkins siamese dream.html 10. Shirley, J. About Retrieved from http://theatomicgarden.com/about 11. Atr magnetics master tape Retrieved from http://www.atrtape.com/index.php 12. Houghton, M. (2010, May). Hybrid systems hardware in the software studio. Sound on Sound Retrieved from http://www.soundonsound.com/sos/may10/articles/hybrid.htm 13. Lavry, D. (2012, May 03). The optimal sample rate for quality audio Retrieved from http://www.l avryengineering.com/lavry white papers/ 14. Robjohns, H. (2007, October). Ssl xlogic x rack. Sound on Sound Retrieved from http://www.soundonsound.com/sos/oct07/articles/sslxlogicxrack.htm

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71 15. Robjohns, H. (2009, January). Tonelux v8 roadster. Sound o n Sound Retrieved from http://www.soundonsound.com/sos/jan09/articles/toneluxv8roadster.htm 16. Harris, B. What is the big deal about 500 series modules Retrieved from http://thedawstudio.com/Gear/500Series.html 17. Electron (or vacuum) tubes Retriev ed from http://www.ieeeghn.org/wiki/index.php/Electron_(or_Vacuum)_Tubes 18. Robjohns, H. (2004, June). Q. is analog mixing superior to digital summing?. Sound on Sound Retrieved from http://www.soundonsound.com/sos/jun04/articles/qa0604 5.htm 19. Coch rane, G. (2004, May 04). Analog summing and why you shouldn't care Retrieved from http://therecordingrevolution.com/2012/05/04/analog summing and why you shouldnt care/ >. 20. Robjohns, H. (2007, July). Rupert neve designs portico 5042 & 5043 dynamics pr ocessors. Sound on Sound Retrieved from http://www.soundonsound.com/sos/jul07/articles/rupertneveportico_5042_5043.htm 21. Tavaglion, R. (2007, March 15). Rupert neve designs portico 5042 'true tape' emulation and line driver. Prosound Network Retrieved from http://www.prosoundnetwork.com/article/rupert neve designs portico 5042 39true tape39 emulation and line driver/690 22. Rivers, M. Mic preamps what you need to know Retrieved from http://mikeriversaudio.files.wordpress.com/2010/10/micpreampsagain _updated.pdf 23. Jung, W. (2004). Op amp applications handbook (1st ed., pp. 767 771). Burlington, MA: Newnes. 24. Lavry, D. (2004). Sampling theory for digital audio Retrieved from http://lavryengineering.com/pdfs/lavry sampling theory.pdf 25. Ting en, P. (2005, September). Steve albini sound engineer extraordinaire. Sound on Sound Retrieved from http://www.soundonsound.com/sos/sep05/articles/albini.htm 26. Tingen, P. (2013, August). Secrets of the mix engineers: a ndrew scheps. Sound on Sound 28 (1 0), 148 157. 27. Doyle, T. (2011, June). Foo fighters: Recording wasting light. Sound on Sound Retrieved from http://www.soundonsound.com/sos/jun11/articles/foo fighters.htm

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72 28. Haeny, J. Waves kramer tape' white paper (analog valve magnetic tape reco rding) Retrieved from http://jo hnhaeny.com/waves white paper/