Aphex Studio Dominator 700 User manual

•
••
STUDIO DOMINATOR™
MODEL 700
~ _.... STUDIO DOMINATOR-'
... 'O'~'~'~ _ •
OPERA TING GUIDE
&
SERVICE MANUAL
•

1.0
2.0
3.0
4.0
5.0
THE STUDIO DOMINATOR
TABLE OF CONTENTS
INTRODUCTION
FUNCTIONAL DESCRIPTION
2.1
2.2
2.3
2.4
2.5
2.6
2.7
Multi-Band Processing vs. Wideband
ALT (Auto Limit Threshold)
EQ, Release Time and TEC
The Gain Control Circuits
The Tracking Control
Output Ceiling Control
Factory Options
A DISCUSSION of GAIN REDUCTION
3.1 Leveling
3.2 Compression
3.3 Compression Ratio
3.4 Operating Threshold
3.5 Attack and Release times
3.6 Limiters and Limiting
3.6.1 Program Limiters
3.6.2 Peak Limiters
3 . 7 Clippers
APPLICATIONS
4.1
4.2
4.3
4.4
4.5
4.6
Broadcast.ing
Recording and Mastering
Live sound
Other Applications
Use with the COMPELLOR
Frequency Response Tailoring
INSTALLATION
5.1 Unpacking
5.2 Input Sensitivity Set
5.3 Mounting
5.4 Connectors
5.5 I/O Considerations
5.5.1 Impedances
5.5.2 Balanced vs. Unbalanced Operation
5.6 AC Line Connector
5.6.1 Voltage Select.ion
5.6 . 2 Fuse Selection
1
3
3
3
4
5
5
5
5
7
7
7
7
8
9
9
11
12
12
13
14
14
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15
16
16
16
16
16
16
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6.0
7.0
8.0
9.0
FRONT PANEL CONTROLS
6.1
Drive
6.2 Output
Ceiling
6.3
Secondary Controls
6.3.1 LF
EQ
6.3.2 LF X-over
6.3.3
HF EQ
6.3.4 HF X-over
6.3.5 Process
On-Off
6.3.6 Tracking
6.3.7
Release Time
6.3.8 TEC
6.4
The
EO
Section
6.5 The TEC Function
FACTORY OPTIONS
19
19
19
20
21
21
22
7.1 Model 702 - With Matrix/De-Matrix 22
7.2 Model 703 - With Pre/De-Emphasis 23
7.3 Model 704 -W/ Pre/De-Emphasis and Lowpass Fltr 24
OPERATING INSTRUCTIONS/SET-UP
8.1
8.2
8.3
8.4
8.5
8.6
8.7
Beginning
Drive
Output Set
Drive Set
Release Time
TEC
Equalization
TECHNICAL DESCRIPTION
9.1 Input Circuit
9.2 Crossover
9.3 VCA Limiters
9.4 Summing Final Limiter
9.5 Process Sample Rectifier
9.6 Output Ceiling circuit
9.7 Output Line Amplifier
9.8 Automatic Limit Threshold (ALT) circuit
9.9 Transient Enhancement Circuit (TEC)
9.10 Metering Circuit
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26
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26
27
27
28
28
29
29
29
30
31
31
31
32
32
32
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10.0 TEST PROCEDURES
10.1 Main Board
10.2 Power/Metering Board
11.0 BLOCK DIAGRAM
12.0 SCHEMATICS and PARTS LISTS
12.1 Input/Bandsplit/L1miters and Power
12.2 Summing/Peak Ceiling/Output/TEC/ALT
13.0 EXPLODED VIEW and MECHANICAL PARTS LISTS
14.0 SPECIFICATIONS
15.0 WARRANTY and SERVICE INFORMATION
16.0 APPLICATION NOTES
33
33
36
38
40
Supply
41
43
45
48
49
50

Studio Dominator - Owner's Manual
1.0 INTRODUCTION
The studio Dominator from Aphex Systems, Ltd. is a stereo
multiband peak limiter designed to fit a wide range of audio
aoplications. ~hrough the use of multiband techniques along
~~h new proprletary circuits the audibility of limiting
action has been greatly reduced, especially when compared to
conventional limiters. This means that greater limiting depth
is possible, resulting in higher loudness with maintained audio
quality. At virtually any limiting depth, the Studio Dominator
is free of "hole punching", "dullness!I, and most other sound
deterioration normally associated with limiters. As a peak
overshoot protection limlter, the Studio Dominator is
undetectable in line while it absolutely prevents peak levels
from exceeding a user settable output level. In addition, the
desired limiting effects of greater audio density, increased
"punch", etc., are readily available with the Studio Dominator.
The Studio Dominator is easy to adjust and use. It is
recommended, however, that the user read this operating manual
in order to fully understand the capabilities of the device and
how to best set up for operation.
The Studio Dominator will find applications in all parts of
the audio industry. Some examples are:
* Sound Contracting- protection of amplifiers and speakers
from overload; increased loudness; maximized use of avail-
able power.
* Recording - preventing sudden
recorder; tightening tracks;
peak overload of mixer
special effects, etc.
or
* Digital Sampling - Obtaining good full scale samples free
from peak overload, i.e . , no more missed samples.
* Digital recording insuring clean recording
AID clipping of peaks and overshoots.
* Satellite Uplink Modulation control
splattering on high frequency audio, reduced
better signal-to-noise ratio.
by stopping
to prevent
distortion,
1

* Broadcasting - AM and FM Modulation control
loudness; cleaner sound; use in production
consistency of tapes, punchier voiceovers.
for greater
tor greater
* Location Film Shoots - anti-crash for dialog and sound
effects recording.
* Post Production
difficult dialog;
Soundtrack peak control; managing
controlling transient sound effects.
* Optical Recording - preventing "valve clash" with higher
average level for low distortion and better signal-to-no!se
performance.
* Analog Disk Mastering - peak control for higher allowable
average cutting levels; less limiter degradation to the
program; brighter, punchier sound.
* C/D Mastering - peak and density control for more accurate
digitizing, cleaner sound requiring less error correction
on playback; no limiter induced sound degradation.
2

2.0 FUNCTIONAL DESCRIPTION
Traditionally, limiters have been designed specifically for
a particular application, or with a mUltitude of interacting
controls that must be adjusted to adapt the unit to a particular
purpose. Because the Studio Dominator circuitry is
"intelligent", only a few basic adjustments are necessary to get
proper results in any application. The user simply sets the
OUTPUT CEILING to the level where peaks must absolutely stop
(such as 100% modulation or just under system overload), and
sets the DRIVE control to obtain the desired amount of limiting.
Some additional controls are provided, but they are mainly for
those who wish to obtain effects from the limiter.
2.1 Multiband vs. Wideband processing
Much of the studio Dominator's high performance is due to a
newly created multiband processing technique that overcomes the
problems previously encountered with both wide- and multi-band
limiting.
One of the main problems of wideband limiting is "spectral
gain intermodulation" or "hole punching", the audible effect of
the more powerful low frequencies, such as a bass drum, causing
the whole program, including the high frequencies, 'to drop
momentarily in level. Wideband limiters also tend to sound dull
for this reason.
Multiband limiting attempts to solve this problem by
splitting the audio into two or more bands, and processing them
separately. But more bands means more parameters to control and
the summing of the separate bands to deal with. For a three
band limiter, the number of controls could easily run to twelve
or more per channel!
The Studio Dominator uses program dependent, II intelligent"
circuits to eliminate all but the most necessary controls. This
dynamic control also tends to make the limiting less audible by
providing the right amount of processing at the right time.
2.2 ALT (Automatic Limit Threshold)
Though free of "hole punching" multiband limiters generally
do not keep the output peak amplitude at a consistent level.
This is due to the varying amount of band energies being added
together together with different amounts of limiting in each
band. Such a characteristic is usually unacceptable (at least
in broadcast applications), so a final clipper is added to chop
down the final level to a reliable amplitude at the expense of
added distortion. Another solution is to add a wideband limiter
3

at the output, but that only re-introduces
wideband limiting and negates the advantages
new solution had to be found.
the problems of
of multiband. A
The answer is a new circuit concept termed ALT (Automatic
Limit Threshold, Pat. pending). Incorporated in the Studio
Dominator, ALT accurately manages output summing levels in a way
that produces no distortion and maintains the full advantages of
multiband limiting.
In the ALT system, the limiter peak output is co~stantly
monitored and adjusted to a reference level by controlling the
limiter thresholds. Below-threshold gain is not changed, so low
level signals are not modified by the ALT process. Since ALT
has a finite reaction time, a soft "catch clipper" is used
following the final summing to stop any brief overshoot
transients. This does not produce any audible distortion
because the ALT prevents all but the briefest overshoots, too
short to hear.
By these methods, the summed signal peak ceiling is
guaranteed to remain at a calibrated value. The maximum output
level can now be made accurately adjustable by a single front
panel control. This is a highly desirable feature not commonly
found on limiters.
Due to intelligent interplay between the ALT control, the
attack timing of the individual bands and the catch clipper, the
"come on" of the limiter is extremely smooth sounding if it can
be heard at all.
2.3 EQ, Release Time and TEe
To
allow for variations in operating conditions and
tailoring of the sound, several features are available on the
Studio Dominator.
The band crossover frequencies are selectable, with the
drive levels into the low and high bands adjustable by ± 6dB.
This allows static and dynamic equalization effects to be
obtained. As the bands get deeper and deeper into limiting, the
EQ effect will diminish as all bands approach equal amplitude.
The release time allows the user to obtain more or less
density (loudness) under heavy limiting. A quicker release time
gives greater loudness by maintaining a small peak-to-average
ratio. The release time may also be used for maximum
transparency at different average amounts of limiting.
All limiters, by their nature, remove transients that
create the live feel in audio. A unique circuit called TEC
(Transient Enhancement Circuit, Pat. pending) restores some of
4

this transient "feel". Output level
psychoacoustic effect is accomplished
modification of the components below
switched in or out as desired.
2.4 The Gain Control Circuits
is not changed, but a
through slight envelope
threshold. TEC may be
Extremely low distortion limiting is accomplished by the
use of type 1537A VCAs in each band coupled with individual
precision comparator/pulse charge gain control circuits. The
attack time is sufficiently fast to prevent audible overshoot
clipping (with the help of ALT) but is slow enough to prevent
"hole punching" by transients such as record pops, etc. The
limiting thresholds for all bands are equal and are DC
programmed by the ALT bus. Release time is likewise equal and
DC controlled.
2.5 Tracking Control
TRACKING locks the gain control signals together for each
band. This provides the most stable stereo image . However,
greatest average loudness is acheived when the two channels are
operated independently.
2.6 Output Ceiling Control
The calibrated OUTPUT CEILING control is the only control
on the studio Dominator that is not a DC control. It is a
precision attenuator that is adjustable in ldB steps from -2dBU
to +21dBU. In-between levels can be accomplished by an internal
trimpot if desired. This setting represents the
actual peak voltage of the output signal, not RMS voltage. This
limit will not by exceeded under ANY conditions of limiting .
The RANGE control selects HI or LOW range of the OUTPUT CEILING
knob.
2.7 Factory options
To adapt the Studio Dominator to the widest varjety of
applications, several factory options are available.
a) Pre/De-emphasis - Allows insertion of a precise
preemphasis curve prior to limiting. Oeemphasis is
jumper selectable to restore flat response if
desired. 75 uSee is standard, others available.
b) Lowpass Filter - In addition to the above, an
overshoot corrected lowpass filter of exceptional
quality may be installed to restrict bandwidth for
broadcast or digital recording. 15kHz is standard.
5

c) Matrix/Dematrlx - For AM stereo, this option
allows L+R and L-R limiting with selectable
de-matrixing.
These options are available as factory installed
only, and are identified by separate model numbers. Refer to
Section 7.0 for further information.
6

3.0 A DISCUSSION OF GAIN REDUCTION
There are several misunderstandings about limiting and
compression among audio professionals. Compression and limiting
are sometimes referred to interchangeably, for example.
To clearly understand the operation of the studio
Dominator, it is good to have a standard definition of terms,
and have a clear understanding of the differences between
leveling, compression, limiting, and clipping. Therefore, this
section will discuss the terminology, offer what we think are
the most accurate definitions, and describe the basic
principles.
3.1 Leveling
"Leveling", or AGC, is control of long-term average levels.
The ratio is fairly high (>10:1), with slow attack and release
times, and a low threshold. Because of the slow operation,
leveling has little or no effect on short-term changes in
average level or on transients.
3.2 Compression and Limiting
"Compression" is a popular contraction of the general term
"dynamic range compression", where "dynamic range" refers to the
difference between the minimum signal level and the maximum
signal level from an audio source over a period of time.
Limiting may be defined as a subset of compression because the
dynamic range is reduced through limiting. However, because
there are significant differences between what are called
"lim1 ters" and 11 compressors" , it is best not to equa te
compression and limiting in application oriented thinking.
Compressors are used principally where it is desired to
force an audio signal to maintain a more constant power level.
This may be to improve the signal-to-noise ratio in a system, to
correct excessively varying volume levels from a program source,
or for effects like gathering greater loudness. One way to
think of this is that compression tries to keep levels from
falling too low. Limiting, in contrast, is used where it is
required that a signal be stopped from exceeding some specific
level. These applications include prevention of overmodulation,
speaker protection, overcutting protection, system overload
protection. transient peak elimination, etc. .For certain
applications it is necessary to combine a compressor and a
limiter to get the desired results. This might be where we are
required to maintain a high average signal level constantly near
7

to but not exceeding the system overload point.
an example of this application.
Broadcasting is
The parameters which mainly differentiate between limiters
and compressors are: compression ratio, operating threshold,
and timing. The circuits to create both types of processors are
essentially similar, using a variable gain cell and a detector
circuit to control the cell. Only the above parameters need be
changed to realize either a limiter or compressor from such a
circuit. Changes in any of the three parameters will result in
significant sonic differences. Therefore, there is not only a
science to designing a good compressor or limiter, but a good
measure of art as well. It is important for the user to
appreciate these factors because he plays an artistic role in
the way he uses and adjusts the equipment.
3.3 Compression Ratio
"Compression ratio" refers to the ratio of a decibel change
of input level to the corresponding decibel change of output
level of a device. Thus, if a 2dB change of input caused a 1dB
change of output, the compression ratio would be 2:1. Perfect
linear circuits produce a 1:1 compression ratio. Compressors
and limiters use compression ratios ranging from about 1.1:1 to
about 30:1. This ratio is sometimes referred to as the
compression "slope". Variable slope compressors are available
which begin compressing with a small ratio and gain ever
increasing ratio as the input signal rises in level. Most
compressors and limiters generate a more or less constant slope,
however. In general, compressors operate with low ratios of
1.1:1 to 3:1; levelers and limiters with greater ratios. from
7:1 to 20:1.
3.4 Operating Threshold
The operating threshold, either refered to as the
"compression threshold" or "limiting threshold" depending on the
processor, is the input referred signal level where dynamic
range modification begins to take place. All limiters and most
compressors operate as linear amplifiers with a relative slope
of 1:1 below this threshold. The most notable exception to this
rule is a compressor associated with some "companding" noise
reduction systems where the compression slope begins close to
the noise floor of the compressor circuit. That is to say that
constant ratio compression takes place over nearly the entire
dynamic range of the system. In all other compressors, the
compression threshold is a user variable setting which
determines the "depth" of compression which will be used. The
lower the threshold setting, the greater amount of compression
is obtained. For limiters, the limiting threshold is also a
user adjustment.
8

The Studio Dominator, rather than making the threshold user
variable, operates with a self controlled threshold. A variable
input gain control is then provided to adjust the "drive" to the
gain controlling and detector circuits, allowing the Output
level control to be precisely calibrated. This method offers
the advantage of optimized noise and distortion design in the
circuitry, calibrated output level, and simplified operation.
3.5 Attack and Release Times'
Timing parameters are extremely critical to the operation
of limiters and compressors. The two timing factors of greatest
importance are attack time and release time (sometimes called
recovery time).
The attack time is the time the processor requires to bring
the input signal under 90% control after the input level exceeds
the operating threshold. Limiters usually incorporate fast
attack times to prevent sudden signal increases from escaping
amplitude control. Compressors usually incorporate slower
attack times to prevent washing out of transient sounds.
Because of this, compressors will generally produce overshoots
at the output well above the average signal level. Often, the
attack time is not adjustable by the user, and thus becomes part
of the characteristic sound of the particular model of
compressor.
Release time is the time required by the processor to
restore itself to 90% of full gain when the input signal drops
below threshold. This time can vary from a fraction of a second
to many seconds depending on the particular device. Very often
this parameter is made user adjustable both for limiters and
compressors even if the attack time is internally fixed. Longer
release time results in less loudness because the gain does not
restore low levels quickly. Faster release time results in
correspondingly greater loudness, but this sometimes comes at
the cost of greater distortion (especially to low frequencies)
and more audibility of the gain control effects.
3.6 Limiters and Limiting
As previously discussed, in order to be effective, a
limiter typically has a threshold above avo, a high compression
ratio(7:1 or greater), and fast attack and release times.
Compressors usually operate at much lower ratios from, say,
1.1:1 to 3:1 in order to maintain a pleasing sound quality
because gain reduction is taking place over a larger dynamic
range. Compressors operating with a high compression ratio are
mostly used when a sound effect is intended. Recording
engineers may use a heavily driven limiter as a compressor when
9

they are looking for more "sustain"
for example. A limiter driven
effectively becomes a compressor.
or a different
to heavy gain
"texture!! J
reduction
Let us now depart from further elaborations about
compressors, and focus on two types of 1 imi teTS : tlpeak
1 imi ters" , and "program 1 imi ters" . At this point it is
important to solidify the definition of "peak level". This term
is taken to mean two different things in the audio industry.
Sometimes it is used to refer to the highest (or peak) VU level
occuring in an audio program. Other times it is used to refer
to the actual peak amplitude of the audio wave, which would be
measured on a peak program meter (ppm) or an oscilloscope
display, but not on a VU meter. Let us define "peak level" as
the true peak waveform amplitude, and "peak program" as the
highest VU level.
3.6.1 Program Limiters
With these definitions in mind, a "program limiter" can
be described as a limiter having all the previously defined
characteristics of a limiter, and whose detection circuits
result in limiting the "peak program" level (as measured on a VU
meter) to a specified level, usually zero VU, without regard for
the peak level .
3.6.2 Peak Limiters
A "peak limiter" is used where the absolute audio waveform
amplitude cannot be allowed to exceed a given value. Most audio
systems produce particularly objectionable distortion when
driven to overload, so peak limiters are often used to maintain
safe peak levels below any system clipping to guarantee a
distortion free system. Limiters in this application are
sometimes referred to as "protection limiters". Another
appl ication of peak 1imi ters is "modulation limi ting " in a
broadcast situation where a specified peak level is defined as
100 percent modulation which must not be exceeded.
Peak limiters are usually characterized by fast
attack and release times, a very high compression ratio and a
high threshold such that no gain reduction takes place for
signals whose peak level is under the overload point of the
system. Limiters wlth very fast release tend to generate
distortion under continuous gain reduction, but for protection
limiting where limiting is brief, the fast action tends to be
practically unnoticeable, maintaining a clean sounding audio
system.
10

3.7 Clippers
Most peak limiters incorporate a final clipper to catch any
amplitude overshoot that may escape the variable gain element
due to the short but finite attack time of the detector circuit.
A properly designed clipper has a virtually instantaneous action
to catch the briefest of transients. This "catch clipper"
usually has little work to do, and because it clips only brief
transients is inaudible in the circuit. Clipping is for
protection, and performs no audible gain reduction.
At this polnt, the reader should be well aware of the
differences between limiters and compressors, and how they might
be used.
1 1

4.0 APPLICATIONS
*
*
*
'"
*
*
*
*
*
Some common applications of limiters are:
Obtaining more loudness
Obtaining more "punch"
Preventing transmitter overmodulation
Preventing tape overload
Preventing system peak overload
Preventing overcutting
Preventing satellite uplink overmodulation
Audio P.A. system protection
Special Effects
Conventional limiters are more suited to certain of these
uses than to others. The Studio Dominator, because of its
intelligent circuitry and optional configurations, is equally
well suited to all limiter uses. This manual will address
several general categories of limiter application and show
typical setups which can serve as the basis for your particular
operation.
4.1 Broadcasting
FM broadcast processing requires special consideration
because of the pre-emphasis curve and bandwidth restrictions
involved. An option card (and a few other simple modifications)
can be installed in the Studio Dominator to produce accurate
operation for FM transmission. With this option, two operating
conditions may be chosen. First, pre-emphasis can be selected
which causes the studio Dominator to output a properly
pre-emphasized signal ready for direct feed into a non
pre-emphasized stereo generator. This is the preferred approach
in most cases. Second, accurate de-emphasis may be selected
after limiting to restore flat system response for feed to a
pre-emphasized stereo generator.
NOTE: If the stereo generator used does not include the
necessary left and right channel 15kHz overshoot compensated
lowpass filters, then the lowpass filter option should be
specified in the Studio Dominator. Many stereo generators
include lowpass filters. but they are not overshoot compensated,
which results in loss of modulation capability. In this case,
the filter should be bypassed or removed and the studio
Dominator filter used.
Setting up the limiter for FM operation is basically
similar to the general set-up procedure. A program signal is
fed into the studio Dominator and drive is adjusted to produce
at least BdB of limitng. Release time should be full fast
12

initially. Raise the peak ceiling control to approach 100
percent modulation on program peaks. The output control
operates in IdB steps so it will probably be necessary to use
the stereo generator input trimmers to achieve the final exact
100 percent modulation setting. If there are no such trimmers
on your stereo generator, you may access the output trimmers
inside the Studio Dominator for a fine adjustment of output
level.
Once the modulation limits are set by the above technique,
the DRIVE, RELEASE TIME, and other controls may be adjusted to
obtain the desired on-air sound. Use of the TEe may be
particularly beneficial since a greater sense of transient
dynamics can be obtained. Additionally, by not turning on the
tracking mode, wider stereo imaging and higher average loudness
can be obtained. The loss of center image stability is not as
severe with the Studio Dominator as expected because the ALT
circuit intelligently tracks the limiting thresholds of left and
right channels.
4.2 Recording and Mastering
a) Tracking
If the tape saturates, if the electronics run out of
he~droom, or if the digital recorder reaches peak input, - you
can no longer "fix it in the mix." By setting the Studio
Dominator output ceiling just below the system's peak level,
these problems will never again occur.
Recording with boosted high end can be safely handled by
the Studio Dominator, preventing tape saturation while
eliminating the need for another equalizer in the signal path.
Using the Studio Dominator. the output of the mic preamp or
input fader may be increased to make a "hotter" recording. This
will effectively increase the signal-to-noise performance so
that noise reduction may no longer be necessary.
b) Mixing
Very often it is desired that a lead track ride out front
of the rest of the mix. By using the studio Dominator on that
track. maximum loudness can be achieved and maintained, allowing
it to stay out front without having to drop the level of the
rest of the mix.
Since the ratio of the Studio Dominator is infinite, any
track driven into consistent deep limiting will not move,
regardless of input level. This is especially useful for bass.
13

c) Mastering
The ideal for mastering is an invisible transfer from tape
to lacquer at the maximum level possible. When using a
conventional limiter to prevent overcutting, the bass or
kickdrum modulates the high end, causing "holes" and loss of
transient 1!feel". If the lead track is very transient, the
whole mix may "duck" during peaks. Due to its multiband
technology and intelligent control circuits, the Studio
Dominator will not cause these effects. At the same time, a
higher level disc may be safely cut with more predictable groove
spacing.
4.3 Live Sound
As with recording electronics, P.A. equipment has headroom
limitations. Although power amps amd speakers may be more
forgiving than digital audio to short term peaks, various types
of audible, objectionable distortion may be generated.
Furthermore, the amps and speakers themselves may be driven to
failure. The studio Dominator not only prevents system overload
while maintaining audio quality, but actually improves overall
system performance. It does this by enabling all parts of the
sound system to safely run at their maximum operating levels,
continuously. A great increase in effeciency may be realized
now that headroom is no longer such a consideration.
Stage monitors always demand maximum controlled loudness.
The Studio Dominator's limiting, crossover and EQ controls allow
precise tailoring of the sound for maximum level before
feedback.
4.4 Other Applications
Once the characteristics of the Studio Dominator are
understood, other applications become obvious, such as -
* Film and Video post-production- The limited dynamic range
and unpleasant sound of overmodulation in these media make
the Studio Dominator an essential tool in any post house.
* Tape Duplication- Master tapes can be recorded at a higher
level, making the dupes "hotter\! with lower noise and
transient distortion.
* Satellite Transmission - Signal-to-noise ratio can be
improved, and pre-emphasis induced high frequency
modulation distortion avoided. Overshoots from companding
can be reducede for greater channel modulation and lower
distortion.
14

* Digital Sampling for synthesizers - Very transient acoustic
sounds can be properly sampled without worrying about
sampler drive levels.
4.5 Use with the Aphex Compellor (Compressor/Leveler)
As previously described, compressors bring low
signals up, and limiters hold high level or peak signals
Using both devices in series gives you both control of
levels (compression) and peak control (limiting).
level
down.
average
Since the Compel lor is the most transparent
compressor/leveler and the Studio Dominator the most effective,
flexible and transparent peak processor, the combination of the
two devices is the ultimate in dynamics control.
4.6 Frequency Response Tailoring
As program audio reaches the onset of limiting, low
frequencies tend to be limited first, due to their greater
energy. The end result is a slight perception of "brightening"
the sound, enhancing impact and transient feel of percussive
sounds as well as aiding intelligibility in most applications.
In the event that absolute flatness of "dynamic" frequency
response 15 desired, a pre- and de-emphasis card may be added to
tailor the limiting curve as needed. See section 7.0 for more
information on factory options.
15

5.0 INSTALLATION
5.1 Unpacking
Your Studio Dominator was carefully packed at the factory,
and the container was designed to protect the unit from rough
handling. Nevertheless, we recommend careful examination of the
shipping carton and its contents for any sign of physical damage
which could have occured in transit. If damage is evident, do
not destroy the container or packing material. Immediately
notify the carrier of a possible claim for damage. Shipping
claims must be made by the consignee.
5.2 Input Sensitivity Set
Before installation the Studio Dominator must be set
for the correct input sensitivity corresponding to the desired
operating level (OVU). It may be set to either -10 or +4 dBm.
The switch for each channel ' is located inside the unit just
behind the input jacks on the main PC board. Simply slide the
switch to the desired position. Towards the power supply is
+4dBm, away is -10dBm. The +4dBm position is suitable for
operating levels from 0 to +lOdBm.
5.3 Mounting
The Studio Dominator occupies one standard rack unit of
space (1 3/4") 19
rr
wide, with a depth of 8 1/2rr. Allow at least
an additional 3" of depth for connectors. Be sure that there is
at least 1/2" of air space around the unit for cooling. Mount
with the cushioned rack screws provided.
5.4 Connectors
The audio inputs and outputs are made with standard XLR
type 3-pin connectors on the rear panel. Equal phase is
maintained from input to output, so the user may elect to use
either pin 2 or pin 3 as high to match his balanced system.
5.5 I/O Considerations
5.5.1 Impedances
The input is of high (160 kOhms) impedance and may be
easily driven by any output source. In the case of
certain situations that need to see a 600 Ohm load, a 600
ohm resistor may be tied across pins 2 and 3 on the input
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