StudioComm 760-03 User manual

50247-1016, Issue 4
© 2016 by Studio Technologies, Inc., all rights reserved
www.studio-tech.com
Model 760-03 Central Controller and
Model 77 Control Console
User Guide
Issue 4, October 2016
This User Guide is applicable for systems consisting of:
Model 760-03: serial number M760-03-00151 and later with
software version 4.20 and higher and FPGA version 4.15 and higher;
Model 77: serial number M77-00151 and later with software version 4.20 and higher
for Surround

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Table of Contents
Revision History ............................................................ 4
Introduction ................................................................... 5
Installation .................................................................... 9
Configuration ................................................................17
Operation ......................................................................39
Technical Notes ............................................................46
Specifications ...............................................................50
Appendix A—Connection Pin-Out Charts ....................52
Appendix B—Sync Input Sources ................................54
Appendix C—Downmix Formulas .................................55

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Revision History
Issue 4, October 2016:
• Revised text for error codes Err1, Err2, and Err3; added text for error code Err4.
Issue 3, April 2015:
• Revised specifications to reflect final audio performance measurements.
Issue 2, January 2015:
• Text clarifications.
• Reflects final product nomenclature (Model 760-03/Model 77).
Issue 1, April 2014:
• Initial release (as Model 76DA-110/Model 77).

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Introduction
What This User Guide Covers
This User Guide is designed to assist
you when installing and using the Model
760-03 Central Controller and one or more
associated Model 77 or Model 71 Control
Consoles.
Overview
As creating and distributing multi-channel
surround (5.1) and stereo audio material
has become a day-to-day reality, the abil-
ity to simply and effectively monitor these
sources is imperative for recording, post-
production, and broadcast facilities. And
with audio-with-picture applications becom-
ing so prevalent, additional monitoring chal-
lenges have arisen. Studio Technologies
has addressed these needs with the Studio-
Comm for Surround Model 760-03 Central
Controller and the Model 77 and Model 71
Control Consoles. With digital audio inputs,
digital and analog monitor outputs, support
for multiple user control surfaces, and an
extensive set of operating resources it’s a
simple task to integrate a monitoring system
into virtually any facility. The carefully se-
lected group of features, including surround
and stereo inputs, configurable input-signal
time delay, multiple pre- and post-fader out-
puts, configurable downmix and mute/solo
functions, and bass management, along
with a multi-format sync input, make the
system powerful yet simple to operate. And
by using the best of contemporary technol-
ogy, as well as following rigorous design
practices, the system’s audio quality is
excellent.
A StudioComm for Surround system starts
with the Model 77 Control Console. It’s the
system’s “command center” and is designed
to reside at a user’s location, allowing fin-
gertip selection of all monitoring functions.
Numerous LED indicators provide com-
plete status information. A 4-digit numeric
display indicates the post-fader monitor
output level in real time. A major strength
of the Model 77 is its ability to configure,
under software control, many important
operating parameters. Intended for sec-
ondary monitoring locations, the Model 71
Control Console is a compact user control
surface. It provides three of the most basic
functions: a rotary level control, dim on/off
button, and reference level on/off button.
Most installations will use only one Model
77 Control Console. However, up to three
additional Model 77 or Model 71 Control
Consoles can also be connected. This
provides multiple users with full control
over a facility’s monitor system. And to
make installation simple, the Model 760-03
provides power for all connected Model 77
or Model 71 units.
The core of this StudioComm for Surround
system is the Model 760-03 Central Con-
troller. The one-rack-space unit contains
circuitry that supports balanced digital
audio inputs, balanced digital and analog
monitor outputs, digital audio and control
processing, and interfacing for the user
control surface(s). The Model 760-03 pro-
vides two surround (5.1) and three stereo
digital audio inputs. These balanced digital
inputs are AES3-compliant; sources of this
type are ubiquitous in many post-produc-
tion and audio facility environments. The
inputs allow a sample rate of up to 192
kHz and a bit depth of up to 24 to be di-
rectly supported. Circuitry associated with
one of the stereo inputs provides sample
rate conversion (SRC) capability, allowing
a wide range of digital audio sources to be
monitored. Up to 340 milliseconds of input

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Figure 1. Model 760-03 Central Controller Front Panel
Figure 2. Model 760-03 Central Controller Back Panel
Sync status
LED
Control console
status LED
Sync
input
Digital monitor
outputs
To/from
Models 77 &
71 Control
Consoles
AC mains input
Remote control inputs
Stereo
input C
delay can be selected to compensate for
processing delays in an associated video
path. For flexibility, two delay values can be
configured, allowing real-time selection as
desired. A number of different signals can
serve as the Model 760-03’s digital audio
timing reference. For synchronization with a
master timing reference a dedicated source
of word clock, DARS (AES11), bi-level
video, or tri-level video can be connected.
Alternately, the L/R connection of the ac-
tively selected surround or stereo input
source can serve as the timing reference.
A range of digital and analog surround (5.1)
and stereo monitor outputs are provided.
The post-fader surround and stereo digital
and analog monitor outputs are intended for
connection to monitor loudspeaker systems.
The pre-fader surround digital monitor out-
put can be used with metering systems that
require signals that aren’t impacted by level
control or other monitoring functions. The
stereo input C direct digital monitor output
allows an installation to directly access the
SRC capabilities. The digital monitor out-
puts are compatible with equipment that re-
quires balanced AES3 digital audio signals
with an output impedance of 110 ohms and
a signal level of 5 volts peak-to-peak (Vpp).
A sophisticated bass management func-
tion is integral to the Model 760-03’s design
and can be enabled if desired. It can apply
to both the surround and stereo digital and
analog post-fader monitor output channels.
Note however that the bass management
function is only supported at sample rates
of 44.1, 48, 88.2, and 96 kHz. The overall
goal of bass management is very simple:
ensure that the entire audio bandwidth of
all channels can be accurately monitored.
Many loudspeaker systems have inher-
ent low-frequency limitations, preventing
a true picture of the source material from
being presented. To overcome this, the low-
frequency energy from the five channels
associated with the surround inputs and the
two channels associated with the stereo
inputs can be separated and routed to the
Analog monitor
outputs
Digital surround (5.1) inputs A & B
and digital stereo inputs A & B

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Figure 3. Model 77 Control Console Front Panel
Channel mute/solo
Mute/solo
mode
Post-fader surround
monitor output
• Surround/stereo
• Reference level
• Mute all
• Dim
• Rotary level control
Monitor output
level display
Input source
select
Downmix
subwoofer (SUB) channel of the monitor
outputs. Several of the bass management
functions can be configured to match the
requirements of specific installations.
Great care was taken in designing the sys-
tem’s architecture, ensuring that the charac-
ter of the audio input signals is preserved.
All audio processing, including bass man-
agement, is performed in 32-bit logic using
a high-speed field-programmable gate array
(FPGA) integrated circuit.
The Model 760-03 occupies one space
(1U) in a standard 19-inch rack. Digital
audio sources are interfaced with the
Model 760-03 using one 25-pin female
D-subminiature connector and one 3-pin
female XLR connector. A BNC connector
is used to interface with an external sync
source. Digital and analog monitor output
signal connections are made using two
25-pin female D-subminiature connectors.
One 9-pin female D-subminiature connector
is used to connect the Model 760-03 with
up to four Model 77 or Model 71 Control
Consoles. A second 9-pin female “D-sub”
connector is used to interface with remote
control signals. AC mains power is con-
nected directly to the Model 760-03, with an
acceptable range of 100 to 240 V, 50/60 Hz.
Additional Details
The Model 77 provides five buttons and as-
sociated LEDs for selection of the surround
and stereo input sources to be monitored.
While in most cases only one input source
will be monitored at a time, stereo input C
can be selected for simultaneous monitoring
with one of the two surround or other two
stereo inputs. This allows the two selected
inputs to be combined (“summed”).
It’s interesting to note that while each of the
two surround inputs has an LFE channel
associated with it, the “.1” post-fader digital
and analog surround monitor outputs are
designated as SUB (subwoofer), rather than
LFE. This terminology was carefully select-
ed to highlight the fact that this output chan-
nel may include more than just LFE content.
The bass management function, if enabled,
will redirect low-frequency energy from the

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main input channels, combining it with the
LFE content before routing the sum to the
digital and analog subwoofer outputs.
The post-fader surround and stereo digital
and analog monitor output levels can be
controlled by way of a large, easy-to-use
rotary control. The control, actually a digital
encoder, allows level selection in precise
0.5-dB steps. The auto mute all function
causes the post-fader surround and stereo
monitor output channels to automatically
mute whenever the output level control
reaches maximum attenuation. Using the
reference level function, the post-fader sur-
round and stereo monitor output levels can
be set to a pre-configured value. This is pro-
vided for audio-with-picture applications that
require a specific monitor output level. The
reference level is easily configured by tak-
ing an electronic “snapshot” of the desired
monitor output level. For user confirmation a
4-digit LED readout can display the level of
the post-fader surround and stereo monitor
output channels. To match the needs of a
facility, it can be configured to display either
the attenuation level or the sound pressure
level (SPL).
The dim function allows the post-fader sur-
round and stereo digital and analog monitor
output levels to be reduced by a fixed dB
amount. The dim level is configured from
among four available values. A mute all
function allows the post-fader surround and
stereo monitor output channels to be simul-
taneously muted. The channel mute/solo
section provides post-fader surround and
stereo channel monitoring control, allowing
a single channel to be muted or monitored.
Multiple channels can also be simultane-
ously selected for muting or “soloing.”
A special solo mode is also provided, called
channel pop solo, which offers a unique
aid when monitoring audio material. Chan-
nel pop solo allows the level of a single
post-fader digital and analog monitor out-
put channel to be raised while the level of
the other channels is reduced. This helps
to emphasize the content on one channel
without fully muting the others. Broadcast
applications can benefit from the channel
pop solo mode by allowing, for example, the
center channel to be highlighted while still
maintaining some level on the other chan-
nels. The amount of level increase—the
“pop”—as well as the amount of attenua-
tion can be configured to meet the needs of
specific applications or users.
Two functions allow the input sources to be
checked for level or phase inconsistencies.
The surround to stereo downmix function is
used to create a stereo signal from the se-
lected surround (5.1) source. Key operating
parameters in the surround to stereo down-
mix function can be configured to meet the
requirements of an application. This can be
especially useful when support for specific
international broadcast standards is re-
quired. The stereo to mono downmix func-
tion allows audio on the left and right input
channels to be added (summed) and moni-
tored on the center output channel. The two
downmix functions can be simultaneously
enabled, allowing a surround source to be
checked for mono compatibility. The down-
mix functions always impact the post-fader
surround and stereo monitor outputs. A
configuration setting allows the pre-fader
surround monitor output to be selected for
pre- or post-downmix operation.
For flexibility, the StudioComm for Surround
system is designed to easily integrate with
equipment such as production intercom
systems, on-air or recording tally signals,

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and audio consoles. Two remote-control
inputs provide access to the mute all and
dim functions. By providing access to
these functions, talkback or slate activity
from an audio console or other communi-
cations system can control the level of the
post-fader surround and stereo monitor
outputs.
Installation
In this section you will be installing the
Model 760-03 Central Controller in an
equipment rack. Connections to the digital
audio inputs, digital monitor outputs, and
analog monitor outputs will be made. A
dedicated digital audio timing reference
signal can be connected to the sync input.
If desired, external equipment will be inter-
faced to the remote control inputs. A loca-
tion will be selected for the first Model 77
Control Console and it will be connected
to the Model 760-03. AC mains power will
be connected to the Model 760-03. For
advanced applications up to three addi-
tional Model 77 or Model 71 Control
Console units can be connected to the
Model 760-03.
System Components
The main shipping carton contains one
each of the following: Model 760-03 Cen-
tral Controller, Model 77 Control Console,
9-pin D-sub interconnecting cable, and
user guide. Also included in the ship-
ping carton is a North-American-standard
AC mains cord. Your dealer or distributor
should provide an AC mains cord appro-
priate for destinations outside of North
America. Any additional Model 77 or Model
71 Control Consoles will be shipped in
separate cartons.
Mounting the Model 760-03
The Model 760-03 Central Controller re-
quires one space (1U) in a standard 19-inch
(48.3 cm) equipment rack. Secure the Model
760-03 into the equipment rack using two
mounting screws per side. Select a location
that is convenient for making connections to
the audio signals as well as interfacing with
the first (or only) Model 77 Control Console.
A cable is supplied to connect the Model
760-03 to the Model 77. If the needs of a
specific installation dictate, an alternate-
length interconnecting cable can be fabri-
cated and used.
Audio Connections
Audio connections are made by way of three
25-pin female D-subminiature connectors
and one 3-pin female XLR connector. All
the connectors are located on the Model
760-03’s back panel. Refer to Figure 2 for
a detailed view of these connectors.
Audio Inputs
Two surround (5.1) and three stereo digi-
tal audio sources can be connected. All
sources can be monitored using the pre-
and post-fader surround and post-fader
stereo monitor output channels. A one-to-
one relationship is maintained between the
input and output channels, i.e., left input to
left monitor output, right input to right moni-
tor output, center input to center monitor
output, etc. (Of course this won’t be true in
the case where the user has enabled one or
both of the downmix functions.) Stereo input
C is also routed to the stereo input C direct
monitor output.
The audio inputs support digital audio sig-
nals with a sampling rate of up to 192 kHz
and a word length (depth) of up to 24 bits.
It’s best if the connected signal sources

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maintain a common sample rate and tim-
ing reference. Having all signals “locked”
together helps to ensure proper handling
by the Model 760-03’s all-digital signal
control path.
There is, however, an exception worth not-
ing. Circuitry associated with stereo input
C has sample rate conversion (SRC) ca-
pability, allowing virtually any digital audio
signal to be connected. A signal connected
to stereo input C can have an independent
sample rate and timing reference and still
be monitored correctly. Refer to the Techni-
cal Notes section of this user guide for a
detailed review of the SRC capability.
The Model 760-03’s digital audio inputs
are intended for connection with balanced
digital audio sources that are compatible
with the AES3 standard. This signal type
has a nominal impedance of 110 ohms
and a nominal signal level of 5 Vpp.
One 25-pin female D-subminiature con-
nector (DB-25F) is used to interface with
the 16 channels associated with surround
input A, surround input B, stereo input A,
and stereo input B. Each of the eight physi-
cal connections supports two audio chan-
nels. Often a wiring assembly prepared for
these digital audio inputs would typically
be identical to that of a TASCAM®-type
(AES59-compliant) input assembly. An as-
sembly of this type would have eight 3-pin
female XLR connectors on one end and
a 25-pin male D-subminiature connector
(DB-25M) on the other. Refer to Figure 4
for details on connecting with the 25-pin
female D-subminiature connector.
On the Model 760-03 stereo input C uses
a 3-pin female XLR connector for interfac-
ing with a digital audio signal source. The
mating cable should have a 3-pin XLR
connector wired such that signal + goes to
pin 2, the – signal to pin 3, and shield to
pin 1.
Unbalanced AES3 digital audio signals
can also be used with the Model 760-03’s
inputs if external coupling transformers
(“baluns”) are utilized. These impedance-
matching (75 ohms to 110 ohms) and level
step-up transformer assemblies typically
provide a BNC connector on their input
and a 3-pin male XLR connector on their
output.
Digital Monitor Outputs
The 25-pin female D-subminiature
connector labeled Digital Monitor Outputs
provides access to the Model 760-03’s
16 channels of digital audio monitor output:
pre-fader surround, post-fader surround,
post-fader stereo, and stereo input C
direct. The pre-fader surround digital
monitor output channels are intended
Signal Signal
Connections Channel High (+) Low (–) Shield
Surround Input A L/R 1 24 12 25
Surround Input A C/LFE 2 10 23 11
Surround Input A LS/RS 3 21 9 22
Stereo Input A 4 7 20 8
Surround Input B L/R 5 18 6 19
Surround Input B C/LFE 6 4 17 5
Surround Input B LS/RS 7 15 3 16
Stereo Input B 8 1 14 2
Notes: 1) All signals transformer-coupled digital audio;
balanced AES3 (110 ohms, 5 Vpp) compatible.
2) Connector type on Model 760-03 is 25-pin female
D-subminiature (DB-25F). Installer must provide male
(DB-25M). Connector uses 4-40 threaded inserts for
locking with mating plug.
3) Wiring scheme follows AES59-2012 convention.
Standard TASCAM-type wiring harnesses are directly
compatible, with the possible exception of 4-40 screw
threads being required.
Figure 4. Connections for Surround A,
Surround B, Stereo A, and Stereo B Digital Inputs

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for connection to metering or monitoring
equipment that requires uninterrupted
full-level signals.
The post-fader surround digital monitor
output channels are intended to connect to
a 5.1 loudspeaker system. The post-fader
stereo digital monitor output is provided to
support a separate set of stereo monitor
loudspeakers.
The stereo input C direct digital monitor
output is essentially a unity gain copy of
the signal connected to stereo input C.
However, the signal does pass through the
sample rate conversion (SRC) and input
delay circuitry. The impact made by these
functions will depend on the specific input
signal and the Model 760-03’s configura-
tion settings.
The digital monitor outputs are balanced
AES3 digital audio sources with a nominal
impedance of 110 ohms and a nominal lev-
el of 5 Vpp. Signals of this type are normal-
ly interconnected to destination equipment
using shielded twisted-pair cable terminat-
ed with 3-pin male XLR connectors.
A cable assembly with a 25-pin male D-
sub connector (DB-25M) on one end and
the desired connectors on the other end
will be used for connecting to the digital
monitor outputs. The D-subminiature con-
nector follows the TASCAM-type wiring
convention, organizing the 25 pins into
eight groups of three pins each; one pin
remains unused. Each set of three pins
provides an independent interface. In the
analog world this would allow eight audio
signals to be transported. But with AES3
digital audio signals this allows support for
16 audio channels; eight interfaces each
supplying two audio channels.
A wiring assembly prepared for the Model
760-03’s monitor outputs would typically be
identical to that of a TASCAM-type output
assembly. An assembly of this type would
have a 25-pin male D-subminiature connec-
tor (DB-25M) on one end and eight 3-pin
male XLR connectors on the other.
For compatibility with balanced AES3 digital
audio signals connect the D-sub’s + ter-
minal as signal high and the – terminal as
signal low. In most applications a 3-pin male
XLR connector will be used. In this case
the + terminal would go to pin 2 of the XLR,
the – terminal to XLR pin 3, and the shield
terminal to XLR pin 1. Refer to Figure 5 or
Appendix A for the exact connection details.
Note that unlike a TASCAM-type assembly,
the two threaded fasteners associated
with the Model 760-03’s D-sub connectors
use 4-40 threads. This complies with the
original design standard for D-subminiature
connectors.
Signal Signal
Connections Channel High (+) Low (–) Shield
Pre-Fader L/R 1 24 12 25
Pre-Fader C/SUB 2 10 23 11
Pre-Fader LS/RS 3 21 9 22
Stereo Input C Direct 4 7 20 8
Post-Fader L/R 5 18 6 19
Post-Fader C/SUB 6 4 17 5
Post-Fader LS/RS 7 15 3 16
Post-Fader Stereo 8 1 14 2
Notes: 1) All signals transformer-coupled digital audio;
balanced AES3 (110 ohms, 5 Vpp) compatible.
2) Connector type on Model 760-03 is 25-pin
female D-subminiature (DB-25F). Installer must
provide male (DB-25M). Connector uses 4-40
threaded inserts for locking with mating plug.
3) Wiring scheme follows AES59-2012 convention.
Standard TASCAM-type wiring harnesses are directly
compatible, with the possible exception of 4-40 screw
threads being required.
Figure 5. Connections for Digital Monitor Outputs

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Pre-Fader Surround Digital Monitor
Output
The pre-fader surround digital monitor
output channels are intended to connect
to metering, measurement, or other
signal monitoring equipment that requires
uninterrupted, full-level digital audio signal
sources.
Stereo Input C Direct Digital Monitor
Output
The stereo input C direct digital monitor
output is intended for use in site-specific
applications. It provides an uninterrupted,
full-level digital audio signal source that
is post-SRC and input delay in the signal
chain.
Post-Fader Surround Digital Monitor
Output
The post-fader surround digital monitor out-
put channels are designed for connection to
digital inputs on audio amplifiers associated
with monitor loudspeakers. Alternately, they
could be connected to the inputs of loud-
speakers that contain integrated amplifiers
with digital audio input capability.
Post-Fader Stereo Digital Monitor Output
The post-fader stereo digital monitor output
channels are intended to support a stereo
loudspeaker system, either by connecting
to the digital input of an amplifier associ-
ated with a set of loudspeakers or directly
to a set of amplified speakers that provide
digital inputs.
Analog Monitor Outputs
The connector labeled Analog Monitor
Outputs provides access to the Model
760-03’s 6-channel (5.1) surround and
2-channel stereo analog monitor outputs.
The surround analog monitor output chan-
nels are intended to connect to analog
inputs associated with the surround loud-
speaker system incorporated in a facility.
The stereo analog monitor output allows
support for a secondary set of stereo
monitor loudspeakers.
The analog monitor output channels are
designed for connection to audio amplifiers
associated with monitor loudspeakers or
to the inputs of loudspeakers that contain
integrated amplifiers. The analog monitor
outputs are electronically balanced and
will perform optimally when driving loads of
2000 (2 k) ohms or greater. In most appli-
cations 3-pin male XLR connectors will be
used to interface with the inputs on the as-
sociated amplifiers or amplified speakers.
In this case the + terminal would go
to pin 2 of the XLR, the – terminal to XLR
pin 3, and the shield terminal to XLR pin 1.
Balanced operation of the analog monitor
outputs is the preferred connection method
but unbalanced operation does not pose a
problem. To connect to an unbalanced load
connect the + terminal as signal high, and
only the Model 760-03’s shield terminal as
the signal low/shield. Leave the – terminal
unconnected. For correct unbalanced op-
eration, it is important not to connect – and
shield together.
The wiring scheme used by the D-submin-
iature connector complies with AES59-
2012, as made popular by TASCAM. A
wiring assembly prepared for the Model
760-03’s analog monitor outputs is identi-
cal to that of a TASCAM-type output as-
sembly. Please refer to Figure 6 for the
exact connection details. Again note that
unlike a TASCAM-type assembly, the
Model 760-03’s D-sub connectors use
4-40 threads.

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Sync Input
The Model 760-03 requires a timing refer-
ence (sync) signal so that the digital audio
input and digital monitor output signals will
be handled correctly. A configuration set-
ting allows the source of sync to be the L/R
input of the currently selected surround
or stereo digital audio input. While this is
acceptable, audio artifacts (clicks or noise)
can occur when switching between inputs.
A better method is to connect a dedicated
timing reference signal to the Model 760-
03’s sync input connector. The connected
sync signal must maintain a stable rela-
tionship between itself and the digital audio
inputs. The actual sync source can be in
one of several formats: word clock, DARS
(AES11), bi-level video, or tri-level video.
An overview of the various compatible
timing reference signals might prove
worthwhile. Word clock is a digital signal
that is locked in phase and frequency to
the sample rate of the associated digital
audio sources. DARS (digital audio refer-
ence source) is a timing signal compliant
with the AES11 standard. It’s sometimes
referred to as “AES3-black.” Technically it is
similar to an AES3 signal but is generated
specifically as a timing reference signal.
Bi-level video sync signals were originally
provided to support NTSC and PAL broad-
cast applications, although they continue
to be used by contemporary equipment.
Tri-level sync signals were primarily asso-
ciated with facilities that supported high-
definition (HD) video equipment, however
the importance of this type of sync seems
to be waning. Both bi-level and tri-level
signals can be found at numerous rate
combinations, configured to allow for com-
patibility with the various video formats.
With the wide range of allowable sync
sources proper Model 760-03 operation
should be easy to obtain. Extensive testing
has been done using many different sync
source types and rates. Interested users
can refer to Appendix B of this user guide
for details.
The external sync reference source is con-
nected to the sync input BNC connector
located on the Model 760-03’s back panel.
For flexibility this input can be configured
to be high-impedance (“floating”) or ter-
minated with an impedance of 75 ohms.
A sync source that is dedicated for use by
the Model 760-03’s sync input will typically
have input termination enabled. If the sync
signal connected to the Model 760-03 is
being connected (“multed”) to other inputs
it may be desirable for the termination to
be disabled. A general “rule of thumb” is
that termination should be applied only
at the location of the last physical device
using a sync signal.
Signal Signal
Connections Channel High (+) Low (–) Shield
Surround L 1 24 12 25
Surround R 2 10 23 11
Surround C 3 21 9 22
Surround SUB 4 7 20 8
Surround LS 5 18 6 19
Surround RS 6 4 17 5
Stereo L 7 15 3 16
Stereo R 8 1 14 2
Notes: 1) Connector type on Model 760-03 is 25-pin female
D-subminiature (DB-25F). Installer must provide male
(DB-25M). Connector uses 4-40 threaded inserts for
locking with mating plug.
2) Wiring scheme follows AES59-2012 convention.
Standard TASCAM-type wiring harnesses are directly
compatible, with the possible exception of 4-40 screw
threads being required.
Figure 6. Connections for Analog Monitor
Outputs

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Page 14 Studio Technologies, Inc.
for Surround
Remote Control Inputs
Support is provided for two remote con-
trol input functions: remote mute all and
remote dim. These functions only impact
the post-fader surround and stereo digital
and analog monitor outputs. The Model
760-03’s inputs use logic gates, “pulled up”
to 3.3 Vdc by way of resistors, which are
active whenever they are brought to their
logic low state. Inputs of this type are com-
monly referred to as GPI inputs. While the
input circuitry is protected from over-current
and static discharge (ESD), care should be
taken to prevent nasty signals from reach-
ing them. The inputs are active only when
held in the low state; they can’t be config-
ured to change state (“latch”) in response to
a logic pulse.
A 9-pin female D-subminiature connector
is used for the remote control inputs. Re-
fer to Figure 7 or Appendix A for the exact
connection details. Note that pin 4 (remote
common) connects to the Model 760-03’s
internal circuit common connection as well
as to the Model 760-03’s chassis and mains
earth connections. Figure 7 also shows two
spare remote control inputs (pins 8 and 9).
These are provided for future applications
and should remain unconnected.
Connecting the Model 760-03
to the Model 77
A 9-pin female D-subminiature connec-
tor, labeled To/From Control Consoles, is
provided on the back panel of the Model
760-03 Central Controller. This is used to
interface the unit with Model 77 Control
Consoles. Refer to Figure 8 or Appendix A
for details. A 9-pin female D-sub connec-
tor, labeled To/From Central Controller, is
provided on the back panel of each Model
77 Control Console. A cable with 9-pin male
D-sub (DE-9M) connectors on each end is
used to interconnect the Model 760-03 with
the Model 77 units. A cable is included in
the shipping carton. The cable implements
all nine connector pins in a one-to-one
manner.
Should an interconnecting cable of a differ-
ent length be required there’s no problem
for one to be fabricated and used. While
it can be wired in a one-to-one fashion
supporting all nine pins, only four con-
nections are required: pin 1 (data +), pin
6 (data –), pin 4 (DC +), and pin 9 (DC
–). The Model 760-03’s connector pin-out
scheme was designed to allow creation
of an interconnecting cable which uses
Signal Pin Direction
Data Shield 1 Shield
Remote Mute All 5 Input
Remote Dim 6 Input
Remote Spare 1 8 Input
Remote Spare 2 9 Input
Remote Common 4 Common
Note: Connector type on Model 760-03 is 9-pin female
D-subminiature (DE-9F). Connector uses 4-40
threaded inserts for locking with mating plug.
Figure 7. Connections for Remote Control
Inputs
Signal Pin Direction
Data + (RS-485) 1 To/From Models 77/71
Data – (RS-485) 6 To/From Models 77/71
Data Shield 2 To/From Models 77/71
DC + (12 V) 4 To Models 77/71
DC – (12 V Return) 9 To Models 77/71
DC Power Shield 5 To/From Models 77/71
Note: Connector type on Model 760-03 is 9-pin female
D-subminiature (DE-9F). Connector uses 4-40
threaded inserts for locking with mating plug.
Figure 8. Connections between Model 760-03
and Model 77 and Model 71

Model 760-03/77 User Guide Issue 4, October 2016
Studio Technologies, Inc. Page 15
for Surround
commonly available 2-pair audio cable. This
cable, consisting of two twisted pairs each
with an individual shield, is typically sleek,
flexible, and available in many colors. One
pair and shield can be used for the data
connections while the other pair and shield
can be used for the DC connections. This
implementation has the advantages of pro-
viding a shield for the data path and a more
robust common connection (two conduc-
tors including the shield) for the DC power
circuit.
A few simple calculations are required to
determine the maximum cable length when
connecting a Model 760-03 to a Model 77.
The differential transmission scheme used
by the system’s RS-485 interface makes
an interconnection in excess of 1000 feet
(>300 meters) easily possible. The limiting
factor is typically the ability of the wiring to
pass the DC power supplied by the Model
760-03 to a Model 77. The Model 760-03
supplies 12 Vdc with a maximum current of
500 milliamperes (mA).
The Model 77 requires a minimum of 9 Vdc,
100 mA, for correct operation. (The voltage
must be measured directly at the Model
77’s 9-pin connector.) So the maximum
interconnecting cable length is directly re-
lated to the resistive voltage losses associ-
ated with the two DC-carrying conductors.
As the Model 760-03 supplies 12 V and the
Model 77 requires 9 V minimum, this di-
rectly leads to a 3 Vdc maximum drop due
to the interconnecting cable. Using Ohm’s
law it’s quite easy to determine whether
the selected cable will support the desired
interconnection length. Calculate the volt-
age drop by multiplying the total resistance
(in ohms) of the proposed cable by 0.1 (the
Model 77’s required current in amperes).
Remember to include the resistance in both
the DC + and DC – wires when calculating
the voltage drop. If it’s greater than
3 V your cable is too long or the wire
gauge is too small.
Additional Control Consoles
Some installations may benefit from the
Model 760-03’s ability to be controlled by
additional control consoles. At least one
Model 77 Control Console must be con-
nected to the Model 760-03 Central Con-
troller. After this requirement has been met
up to three additional Model 77 or Model
71 Control Consoles can also be connect-
ed and to powered by the Model 760-03.
When connecting multiple control consoles
to a Model 760-03 all nine pins of each
interconnecting cable can be connected in
parallel (“multed”). Using this arrangement
the data and 12 Vdc power signals be-
tween all the units will be multed. A custom
cable implementation requires just four
pins to be connected: pin 1 (data +), pin 6
(data –), pin 4 (DC +), and pin 9 (DC –).
To make installation simple, a “bus” cable
assembly can be created using a short
length of ribbon cable with one male and
multiple 9-pin female D-subminiature insu-
lation-displacement connectors attached.
Then standard 9-pin cables can link the
control consoles with the connectors on
the bus cable.
Refer to the previous paragraphs of this
user guide where the issues involving
Model 760-03 to Model 77 cable length
are discussed. Note the required current
for a Model 77 is 100 mA while a Model
71 requires only 35 mA. It’s important to
review this information prior to creating
the interconnection scheme to be used for
installing multiple Model 77 units.

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AC Mains Power
The Model 760-03 operates directly from
AC mains power of 100 to 240 V, 50/60 Hz.
Being a “universal input” device, there are
no switches to set or jumpers to install to
match a location’s mains voltage. The unit
uses a 3-pin IEC 320 C14-type inlet con-
nector to mate with a detachable mains
cord. All units are supplied with a mains
cord that has a North-American-standard
plug (NEMA 5-15L) on one end and an IEC
320 C13 socket on the other. Units bound
for other destinations require that the appro-
priate cord be used. The wire colors in the
mains cord must conform to the internation-
ally recognized color code and should be
terminated accordingly:
Connection Wire Color
Neutral (N) Light Blue
Line (L) Brown
Protective Earth (E) Green/Yellow
Safety Warning: The Model 760-03
does not contain an AC mains discon-
nect switch; the AC mains cord plug
serves as the disconnection device.
Safety considerations require that the
plug and associated outlet be easily
accessible to allow rapid disconnec-
tion of AC mains power should it prove
necessary.
As soon as mains power is applied the
Model 760-03 will perform a power-up
sequence. The two LEDs on the right side
of the front panel will individually light in a
rapid right-to-left test sequence. Then the
LEDs will flash in cadence while the firm-
ware loads into the Model 760-03’s main
logic device. After just a few seconds initial
system operation will commence and the
two LEDs will perform their intended func-
tions. Once operating data is being inter-
changed with the one or more connected
Model 77 or Model 71 Control Consoles
the control console status LED will also
light. The sync status LED will light if a valid
sync source has been recognized. The sync
status LED will flash if a valid sync source
is not recognized.
Also upon application of mains power, all
connected Model 77 units will go through
a power-up sequence, lighting each of its
LEDs in succession. Using its 4-digit dis-
play, each Model 77 will then momentarily
display its address, its software version, and
the main and logic device software versions
of the associated Model 760-03.
All connected Model 71 units will also go
through a power-up sequence after mains
power is applied to the Model 760-03. Each
of the Model 71’s three LEDs will light
momentarily. After these LEDs have been
lit, the device address will be shown briefly
using the dim and reference level LEDs,
as shown in Figure 9 in the Configuration
section. When this is complete the Model 71
will begin normal operation and its status
LED will light if communication is estab-
lished with the Model 760-03. If the Model
71’s status LED does not light check to see
if there is a device address conflict among
all connected control consoles and that all
cables are connected properly.
Should an error be detected during the
start-up process the two LEDs on the Model
760-03’s front panel will continue to flash in
cadence indefinitely. On the Model 77 units
a diagnostic code may be displayed. Refer
to the Technical Notes section of this user
guide for details.

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for Surround
Only after the Model 760-03 and all con-
nected Model 77 and Model 71 units have
correctly powered up will full system oper-
ation begin. It’s possible that audio signals
will first be present on the digital monitor
outputs. The analog monitor outputs will
only become active after a protection inter-
val has elapsed. These outputs are muted
using electro-mechanical relays that oper-
ate under software control.
Configuration
After the physical installation has been
completed it’s important that the system’s
configuration options be carefully reviewed.
In most cases one or more of the operating
parameters will need to be revised to meet
the needs of the specific installation. Many
of the configuration parameters will impact
the signal flow in to and out of the Model
760-03 Central Controller. Other param-
eters affect how the one or more Model
77 Control Consoles will display status
conditions and respond to user commands.
Most of the configuration choices will be
made using a Model 77 Control Console.
However, two configuration choices are
available for each of the connected Model
71 Control Consoles.
Configurable Parameters
Many StudioComm functions can be con-
figured to meet the exact needs of an
installation. A Model 77 Control Console
is used to display and select the desired
system configuration. Here’s an overview
of what can be configured:
• Model 77 Device Address (must be
unique for each unit!)
• Stereo Input C Sample Rate Converter
• Post-Fader Stereo Digital and Analog
Monitor Output
• Bass Management
• Mute/Solo Bass Management Mode
• Sync Source
• Sync Input Termination
• Audio-Synced-to-Video Sample Rate
• Reference Level
• Overall Display Mode
• Reference Level in dB SPL
• Auto Reference Level Off
• Dim Level
• Remote Inputs
• Surround to Stereo Downmix Levels
• Pre-Fader Surround Digital Monitor
Output Mode
• Channel Pop Solo Mode Offset Levels
• Input Delay A and B
• Post-Fader Digital and Analog Monitor
Output Channel Level Offsets
The configuration diagrams, located later
in this section, give details on setting each
parameter. An overview of each configu-
rable parameter is provided in the following
paragraphs.
Entering and Exiting the
Configuration Mode
A small button is located on the back of
each Model 77 Control Console, adjacent
to its 9-pin female D-sub connector. On
any connected Model 77 pressing and
holding this button for two seconds places
both this specific unit and the Model 760-03
into their configuration modes. Other con-
nected Model 77 and Model 71 units will

Issue 4, October 2016 Model 760-03/77 User Guide
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enter a standby mode. When the Model
760-03 enters its configuration mode it will
immediately mute the monitor outputs as a
speaker protection measure. When a Model
77 enters the configuration mode its array
of buttons and LEDs no longer perform their
normal functions, instead they are used
to display the operating parameters and
reflect configuration changes as they are
made.
As a user aid, a Model 77 that has entered
the configuration mode will have its mute
and solo LEDs (associated with the chan-
nel mute/solo section) light in an alternating
manner. Other connected Model 77 units
will indicate that they have entered the
standby mode by simultaneously flashing
their mute and solo LEDs.
To leave the configuration mode and return
the system to normal operation requires
one last action to be made on the Model 77
unit that’s in its configuration mode; press
and hold its configure the button for two
seconds. Note that configuration changes
are stored in nonvolatile memory only after
the configuration mode has been exited.
Our apologies to those of you who find the
configuration button a pain to use, but it’s
supposed to be that way! Seriously, the top
of the button is slightly recessed from the
back panel, making it harder to accidentally
activate. We didn’t want normal operation to
cease because someone pushed a Model
77 into a “rats nest” of schedules, memos
from management, and empty coffee cups!
But a firm press with the fleshy part of an
index finger should do the trick.
There is no problem frequently “tweak-
ing” the system’s operating parameters
to achieve the desired performance. The
configuration data is stored in nonvolatile
memory, which is rated for thousands of
read and write cycles and a retention time
in tens of years. Note that memory integrat-
ed circuits are located in the Model 760-03
Central Controller as well as the Model 77
and Model 71 Control Consoles. The in-
dividual device address is stored in each
Model 77. The device address and button
configuration parameters are stored in the
Model 71. All other configuration param-
eters are stored in the Model 760-03.
Model 77 Device Address
A unique device address must be assigned
to each Model 77 that is connected to a
Model 760-03. The choices are A1, A2, A3,
or A4, with the default address being A1. As
most installations will find only one Model
77 utilized, its default setting is appropri-
ate. For installations that use a second,
third, or fourth Model 77 each unit must be
configured with a unique device address.
Problems will occur if more than one unit
has the same address! It’s important to
highlight the fact that the device address is
the only setting that must be done on each
individual Model 77 unit. All other settings
can be made on any one of the connected
Model 77 units. Be sure that any selected
address does not conflict with addresses to
be assigned to Model 71 units.
Stereo Input C Sample Rate
Converter
Circuitry associated with stereo input C can
provide sample rate conversion (SRC) for
digital audio signals connected to that input.
The acceptable input range for sample rate
conversion is very wide, but is dependent
upon the output sample rate. With an out-
put sample rate of 48 kHz any signal with
a sample rate over a range of 8 to 216 kHz
can be properly monitored by the system.
This capability can be especially useful with

Model 760-03/77 User Guide Issue 4, October 2016
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for Surround
signals that are not synchronized with re-
spect to the others connected to the Model
760-03, even if the sample rate is identical.
The only compromise is that the SRC pro-
cess adds a fixed input-to-output (group)
delay of approximately 1 millisecond, a
value that shouldn’t impact most installa-
tions. As such, it’s recommended that the
sample rate converter remain enabled.
However there might be special cases
where this resource isn’t desired and it can
be disabled.
Post-Fader Stereo Digital and
Analog Monitor Outputs
In addition to the post-fader surround digi-
tal and analog monitor outputs, separate
post-fader stereo digital and analog moni-
tor outputs are also provided. By default
the stereo outputs can be enabled by a
user. In applications where stereo monitor
loudspeakers are not connected to either
of the post-fader stereo monitor outputs,
the outputs can be disabled. This can
minimize confusion, preventing a user from
attempting to select the post-fader stereo
digital and analog monitor outputs.
Bass Management
The Model 760-03 incorporates flexible
and sonically excellent bass management
capabilities which can impact both the digi-
tal and analog post-fader monitor outputs.
It is, however, limited to functioning only at
sample rates of 44.1, 48, 88.2, and 96 kHz.
Five configuration parameters are used to
enable or disable bass management as
well as to select the characteristics of the
associated audio filters. While the settings
are simple to make, great care must be
taken in first reviewing the entire monitor
system. Only after a full understanding of
the performance of the associated sur-
round and, if present, stereo loudspeaker
systems are determined can a plan for
bass management be established.
Bass management can be enabled so that
the function is active when the surround
post-fader monitor outputs are enabled. It
can also be independently enabled so that
it can be active when the stereo post-fader
monitor outputs are enabled. By default
bass management for both outputs is
disabled. The crossover point of the bass
management filters can be selected from
among four choices: 40, 50, 60, or 80 Hz.
The slope of the low-pass and high-pass
filters associated with bass management
can be independently selected. The choic-
es are 12 dB-per-octave or 24 dB-per-
octave with the latter being the default.
Mute/Solo Bass Management
Mode
The Model 760-03’s mute/solo function can
be configured for how it performs in appli-
cations where bass management has been
enabled. This is a somewhat-esoteric topic
but can be important in certain situations.
The default setting for the mute/solo bass
management mode is for pre-bass man-
agement. This means that if a channel has
been selected for, as an example, soloing
then the bass management filters will send
any applicable low-frequency content to
the post-fader digital and analog subwoof-
er outputs. So in this case the solo function
is really an “input channel” solo since the
actual acoustical energy associated with
that channel will be reproduced by both the
main channel and subwoofer loudspeak-
ers. So while one is “soloing” a channel (or
set of channels) two or more loudspeakers
may be reproducing the signals.

Issue 4, October 2016 Model 760-03/77 User Guide
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for Surround
The mute/solos bass management mode
can also be set for post-bass manage-
ment. When this mode is enabled a chan-
nel selected for soloing will cause only its
associated post-fader digital and analog
monitor output channels to remain ac-
tive. So if, for example, one of the main
surround input channels (one of the “5.”
channels) is selected for soloing then all
post-fader output channels except that one
will mute. The bass management filters
will remain enabled, thus sending only the
high-passed audio energy from the soloed
input channel to the soloed output channel.
Only if the LFE channel has been selected
for soloing will the subwoofer output re-
main active. Typically the only reason why
the post-bass management mode would
be selected is when troubleshooting issues
with the loudspeaker system.
Sync Source
The Model 760-03 requires that the desig-
nated external timing reference (sync) be
defined. Three of the choices—word clock,
DARS, and video—are associated with a
signal that is connected to the sync input
BNC connector. The fourth choice allows
the L/R input of the currently selected sur-
round or stereo digital audio input to serve
as the system’s sync source.
Sync Input Termination
The sync input circuitry can be configured
to terminate the signal connected to the
back-panel sync input BNC connector.
When termination is selected a 75 ohm
load is applied to the signal. When the
sync input is not terminated the input im-
pedance is very high, essentially applying
no load to the source. If the sync source
is connected only to the Model 760-03
then enabling termination is typically
appropriate. However, if the sync source is
being “shared” by multiple inputs then care
must be taken so that the signal is only ter-
minated by one device.
Audio-Synced-to-Video
Sample Rate
If a video sync signal is being used as the
Model 760-03’s timing reference the sample
rate of the connected digital audio signals
must be specified. In most cases the de-
fault value of 48 kHz will be appropriate, but
rates from 32 to 192 kHz are available.
Reference Level
For audio-with-picture applications it’s often
beneficial for monitoring to be done in refer-
ence to a known loudspeaker level. This is
often referred to as “mixing to 85 dB” on the
monitors. The StudioComm for Surround
system allows a precise post-fader surround
digital and analog monitor output level to be
stored, and then enabled by pressing the
Model 77 button labeled Reference Level.
Setting the reference level is very simple
but care is required. Typically this will be
done in reference to the surround monitor
output, rather than the stereo monitor
output:
1. Set up a precision sound pressure level
(SPL) measuring device at the desired
listening location.
2. Place the StudioComm system in the
normal operating mode, not the con-
figuration mode. Be certain that the dim,
mute all, reference level, and downmix
functions are not active. The remote
mute all and remote dim functions must
also not be active.