760-03/77 User Guide_4
for Surround
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
© 2016 by Studio Technologies, Inc., all rights reserved
www.studio-tech.com
50247-1016, Issue 4
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for Surround
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
Model 760-03/77 User Guide
Studio Technologies, Inc.
Issue 4, October 2016
Page 3
for Surround
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).
Issue 4, October 2016
Page 4
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
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 ability to simply and effectively monitor these
sources is imperative for recording, postproduction, and broadcast facilities. And
with audio-with-picture applications becoming so prevalent, additional monitoring challenges have arisen. Studio Technologies
has addressed these needs with the StudioComm 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 selected group of features, including surround
and stereo inputs, configurable input-signal
time delay, multiple pre- and post-fader outputs, 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 technology, 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
Model 760-03/77 User Guide
Studio Technologies, Inc.
to reside at a user’s location, allowing fingertip selection of all monitoring functions.
Numerous LED indicators provide complete 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 secondary 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 Controller. 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 provides 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-production 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 directly 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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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 actively selected surround or stereo input
source can serve as the timing reference.
SRC capabilities. The digital monitor outputs are compatible with equipment that requires 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 function 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 inherent low-frequency limitations, preventing
a true picture of the source material from
being presented. To overcome this, the lowfrequency 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
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 output 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
Figure 1. Model 760-03 Central Controller Front Panel
Control console
status LED
Sync status
LED
Figure 2. Model 760-03 Central Controller Back Panel
AC mains input
To/from
Models 77 &
71 Control
Consoles
Remote control inputs
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Digital monitor
outputs
Sync
input
Stereo
input C
Digital surround (5.1) inputs A & B
and digital stereo inputs A & B
Analog monitor
outputs
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for Surround
Channel mute/solo
Mute/solo
mode
Downmix
Input source
select
Monitor output
level display
Post-fader surround
monitor output
• Surround/stereo
• Reference level
• Mute all
• Dim
• Rotary level control
Figure 3. Model 77 Control Console Front Panel
subwoofer (SUB) channel of the monitor
outputs. Several of the bass management
functions can be configured to match the
requirements of specific installations.
connector is used to interface with remote
control signals. AC mains power is connected directly to the Model 760-03, with an
acceptable range of 100 to 240 V, 50/60 Hz.
Great care was taken in designing the system’s architecture, ensuring that the character of the audio input signals is preserved.
All audio processing, including bass management, is performed in 32-bit logic using
a high-speed field-programmable gate array
(FPGA) integrated circuit.
Additional Details
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”
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Studio Technologies, Inc.
The Model 77 provides five buttons and associated 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 selected to highlight the fact that this output channel may include more than just LFE content.
The bass management function, if enabled,
will redirect low-frequency energy from the
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for Surround
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 surround and stereo monitor output levels can
be set to a pre-configured value. This is provided for audio-with-picture applications that
require a specific monitor output level. The
reference level is easily configured by taking 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 surround 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 simultaneously 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 simultaneously selected for muting or “soloing.”
A special solo mode is also provided, called
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channel pop solo, which offers a unique
aid when monitoring audio material. Channel pop solo allows the level of a single
post-fader digital and analog monitor output 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 channels. The amount of level increase—the
“pop”—as well as the amount of attenuation 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 selected surround (5.1) source. Key operating
parameters in the surround to stereo downmix function can be configured to meet the
requirements of an application. This can be
especially useful when support for specific
international broadcast standards is required. The stereo to mono downmix function allows audio on the left and right input
channels to be added (summed) and monitored on the center output channel. The two
downmix functions can be simultaneously
enabled, allowing a surround source to be
checked for mono compatibility. The downmix 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,
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
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 communications 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 interfaced to the remote control inputs. A location 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 additional 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 Central Controller, Model 77 Control Console,
9-pin D-sub interconnecting cable, and
user guide. Also included in the shipping carton is a North-American-standard
AC mains cord. Your dealer or distributor
should provide an AC mains cord appropriate for destinations outside of North
America. Any additional Model 77 or Model
71 Control Consoles will be shipped in
separate cartons.
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Studio Technologies, Inc.
Mounting the Model 760-03
The Model 760-03 Central Controller requires 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 alternatelength interconnecting cable can be fabricated 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 digital audio sources can be connected. All
sources can be monitored using the preand post-fader surround and post-fader
stereo monitor output channels. A one-toone relationship is maintained between the
input and output channels, i.e., left input to
left monitor output, right input to right monitor 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 signals 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 timing 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 noting. Circuitry associated with stereo input
C has sample rate conversion (SRC) capability, 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 Technical 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 connector (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 physical connections supports two audio channels. 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 assembly 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 interfacing with a digital audio signal source. The
mating cable should have a 3-pin XLR
Issue 4, October 2016
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Channel
Signal
High (+)
Signal
Low (–)
Shield
Surround Input A L/R
1
24
12
25
Connections
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
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 impedancematching (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
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
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 configuration settings.
The digital monitor outputs are balanced
AES3 digital audio sources with a nominal
impedance of 110 ohms and a nominal level of 5 Vpp. Signals of this type are normally interconnected to destination equipment
using shielded twisted-pair cable terminated with 3-pin male XLR connectors.
A cable assembly with a 25-pin male Dsub 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 connector 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.
Model 760-03/77 User Guide
Studio Technologies, Inc.
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 connector (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 + terminal 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.
Connections
Channel
Signal
High (+)
Signal
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
19
Post-Fader L/R
5
18
6
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 output channels are designed for connection to
digital inputs on audio amplifiers associated
with monitor loudspeakers. Alternately, they
could be connected to the inputs of loudspeakers 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 associated 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.
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The surround analog monitor output channels are intended to connect to analog
inputs associated with the surround loudspeaker 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 applications 3-pin male XLR connectors will be
used to interface with the inputs on the associated 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 operation, it is important not to connect – and
shield together.
The wiring scheme used by the D-subminiature connector complies with AES592012, as made popular by TASCAM. A
wiring assembly prepared for the Model
760-03’s analog monitor outputs is identical to that of a TASCAM-type output assembly. 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.
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
Connections
Channel
Signal
High (+)
1
24
12
25
Surround L
Signal
Low (–)
Shield
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
Sync Input
The Model 760-03 requires a timing reference (sync) signal so that the digital audio
input and digital monitor output signals will
be handled correctly. A configuration setting 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 76003’s sync input connector. The connected
sync signal must maintain a stable relationship 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
Model 760-03/77 User Guide
Studio Technologies, Inc.
audio sources. DARS (digital audio reference 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 broadcast applications, although they continue
to be used by contemporary equipment.
Tri-level sync signals were primarily associated with facilities that supported highdefinition (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 compatibility 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 connected 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 terminated 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.
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Remote Control Inputs
Support is provided for two remote control 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 commonly 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 reaching them. The inputs are active only when
held in the low state; they can’t be configured to change state (“latch”) in response to
a logic pulse.
A 9-pin female D-subminiature connector
is used for the remote control inputs. Refer 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 connector, 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 connector, 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 different 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 connections 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
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.
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
Figure 7. Connections for Remote Control
Inputs
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Model 760-03/77 User Guide
Studio Technologies, Inc.
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 providing a shield for the data path and a more
robust common connection (two conductors 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 related to the resistive voltage losses associated with the two DC-carrying conductors.
As the Model 760-03 supplies 12 V and the
Model 77 requires 9 V minimum, this directly 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 voltage 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
Model 760-03/77 User Guide
Studio Technologies, Inc.
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 connected to the Model 760-03 Central Controller. After this requirement has been met
up to three additional Model 77 or Model
71 Control Consoles can also be connected 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 between 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 insulation-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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for Surround
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 connector 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 appropriate cord be used. The wire colors in the
mains cord must conform to the internationally recognized color code and should be
terminated accordingly:
Connection
Neutral (N)
Line (L)
Protective Earth (E)
Wire Color
Light Blue
Brown
Green/Yellow
Safety Warning: The Model 760-03
does not contain an AC mains disconnect 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 disconnection 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 firmware loads into the Model 760-03’s main
logic device. After just a few seconds initial
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system operation will commence and the
two LEDs will perform their intended functions. Once operating data is being interchanged 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 display, 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 established 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.
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
Only after the Model 760-03 and all connected Model 77 and Model 71 units have
correctly powered up will full system operation 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 interval has elapsed. These outputs are muted
using electro-mechanical relays that operate under software control.
• Post-Fader Stereo Digital and Analog
Monitor Output
Configuration
• Overall Display Mode
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 parameters 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 configured 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
Model 760-03/77 User Guide
Studio Technologies, Inc.
• Bass Management
• Mute/Solo Bass Management Mode
• Sync Source
• Sync Input Termination
• Audio-Synced-to-Video Sample Rate
• Reference Level
• 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 configurable 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 connected Model 77 and Model 71 units will
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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.
read and write cycles and a retention time
in tens of years. Note that memory integrated circuits are located in the Model 760-03
Central Controller as well as the Model 77
and Model 71 Control Consoles. The individual device address is stored in each
Model 77. The device address and button
configuration parameters are stored in the
Model 71. All other configuration parameters are stored in the Model 760-03.
As a user aid, a Model 77 that has entered
the configuration mode will have its mute
and solo LEDs (associated with the channel 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.
Model 77 Device Address
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 “tweaking” the system’s operating parameters
to achieve the desired performance. The
configuration data is stored in nonvolatile
memory, which is rated for thousands of
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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 appropriate. 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 output 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
Studio Technologies, Inc.
for Surround
signals that are not synchronized with respect to the others connected to the Model
760-03, even if the sample rate is identical.
The only compromise is that the SRC process adds a fixed input-to-output (group)
delay of approximately 1 millisecond, a
value that shouldn’t impact most installations. 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 digital and analog monitor outputs, separate
post-fader stereo digital and analog monitor 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 digital 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
Model 760-03/77 User Guide
Studio Technologies, Inc.
the performance of the associated surround 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 choices are 12 dB-per-octave or 24 dB-peroctave 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 applications 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 management. 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 subwoofer 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 loudspeakers. So while one is “soloing” a channel (or
set of channels) two or more loudspeakers
may be reproducing the signals.
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The mute/solos bass management mode
can also be set for post-bass management. When this mode is enabled a channel selected for soloing will cause only its
associated post-fader digital and analog
monitor output channels to remain active. 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 remain 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 designated 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 surround 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 impedance is very high, essentially applying
no load to the source. If the sync source
is connected only to the Model 760-03
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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 terminated 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 default 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 reference 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 configuration 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.
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
3. Use the Model 77 Control Console to
select the input source that contains the
desired reference signal source, e.g.,
pink noise.
4. Observing the SPL meter, adjust the
Model 77’s rotary level control until the
desired loudspeaker system reference
level has been reached.
5. Being careful not to disturb the position
of the rotary level control, enter the configuration mode by pressing and holding
the configuration button located on the
Model 77’s back panel.
6. Once the configuration mode has been
entered, all the monitor outputs (digital
and analog) will mute. Press and hold
the reference level button; its associated LED will begin to flash. After five
seconds the LED will light steadily to
indicate that a “snapshot” of the new reference level has been taken. The Model
77’s numeric display will then show the
value of the new reference level. The
value shown will always be a negative
number as it’s always a value less than
the maximum output level. The reference level button can now be released.
7. To complete the process the configuration mode must be exited. This is performed by again pressing and holding
the configuration button for two seconds.
The new reference level is now stored in
the Model 760-03’s nonvolatile memory.
Only by repeating the entire procedure
can the value be changed.
Once the configuration mode has been exited, the digital and analog monitor outputs
will again become active. Confirm that the
correct level has been stored by pressing
the reference level button. The SPL meter
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Studio Technologies, Inc.
should display the desired level. If not,
repeat the calibration procedure to achieve
the desired goal.
You might wonder why you have to press
and hold the reference level button for
five seconds before the selected value is
recognized. This is provided specifically so
that unauthorized users won’t accidentally
change the reference level while they experiment with the configuration mode. Only
if you know the “secret” will you be able to
store a new value.
Overall Display Mode
The Model 77’s 4-digit numeric display
can be configured to display the post-fader
digital and analog monitor output levels
in either an attenuation mode or an SPL
mode. In the attenuation mode the output
level is shown as a reduction in level, in
dB, relative to the maximum output level.
When the rotary control is used to set the
output level to its maximum the display will
show 0.0. As the rotary control is turned in
the counterclockwise direction the display
will show negative values, reaching –70.0
before the full mute function automatically
mutes the monitor outputs.
In the SPL mode the display can be configured to allow the output level to be
presented to users in terms of the actual
sound pressure level (SPL). It is used in
conjunction with the reference level in dB
SPL configuration and the stored reference
level. The SPL mode allows a user to see
a visual representation of the SPL level
that is present in the listening environment.
While it takes a little more care to correctly
implement the SPL display mode, it can
offer an enhanced experience for StudioComm users.
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Reference Level in dB SPL
Remote Mute All
The reference level in dB SPL configuration allows a specific SPL value to be
associated with the stored reference level
value. In this way whenever the post-fader
digital and analog monitor outputs are at
their reference level, either through activating the reference level function or manually adjusting the rotary level control, the
Model 77’s display will show the configured
SPL level. Whenever the monitor output is
not at the reference value the display will
show the current value, in dB, relative to
the reference level. The reference level in
dB SPL can be configured over a range of
70.0 to 100.0 dB in 1.0-dB steps. In many
applications selecting a value of 85 would
be appropriate, reflecting the widely used
audio-for-picture 85 dB monitoring reference level. (Typically this 85 dB is really
85 dBC, indicating that a C-weighting filter
has been applied to the measurement.)
Other common reference SPL values, such
as 82 dB and 87 dB, are well within the allowable range.
Two configuration choices are associated
with the remote mute all function: disabled
and enabled. To utilize the remote mute all
function simply requires you to select the
enabled setting.
Auto Reference Level Off
When auto reference level off is enabled,
the function automatically turns the reference level function off if a change is made
to the rotary level control while the reference level function is active.
Dim Level
The dim function is used to reduce the
post-fader digital and analog monitor
output levels by a preset amount. The
reduction is in dB relative to the post-fader
monitor outputs’ current level. There are
four dim level values available: –10.0,
–15.0, –20.0, and –25.0 dB.
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Remote Dim
Two configuration choices are associated
with the remote dim function: disabled and
enabled. To utilize the remote dim function
simply configure it for enabled.
Input Delay
A time delay can be added to the input
signals, allowing compensation for delays
that may be present on associated video
signals. The time delay applies to all input
signals and cannot be applied selectively.
A configured delay time is referenced to a
sample rate of 48 kHz. In the case of input
signals with a sample rate of 48 kHz the
delay range is 0 to 340 milliseconds in
1-millisecond steps. For other sample rates
the time must be linearly scaled. For example, for a sample rate of 96 kHz the actual
time range is 0 to 170 milliseconds. In this
case selecting a delay of 120 on the Model
77 will result in an actual time delay of 60
milliseconds.
For operating flexibility two different input
delay values can be selected and stored
during the configuration process. These
can then be enabled as required by the
user during normal system operation. The
default value for both Delay A and Delay B
is 0 milliseconds. Typical applications would
require only one input delay to be configured. But in other cases two different, both
non-zero, input delay values will be selected. This could be appropriate in applications where multiple video display systems
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Studio Technologies, Inc.
for Surround
are being used in the same control room
or monitoring facility. Each video display
may exhibit its own processing latency and
audio would need to be “lined up” accordingly. During normal StudioComm operation a user can select the appropriate input
delay for the display system currently being
utilized.
Surround to Stereo Downmix
Levels
The surround to stereo downmix function is
a useful tool for checking the compatibility
of surround (5.1) input signals with stereo
and monaural playback environments. The
exact technical formula for how the Model
760-03 handles the surround to stereo
downmix function can be selected by way
of four configurable parameters. The default
settings create a good general-purpose
function that’s effectively used by numerous
users of Studio Technologies’ StudioComm
for Surround products. But there are application-specific situations where modifying one or more of the parameters will be
appropriate. This can be in response to a
personal choice in monitoring methods or,
more frequently, to meet the requirements
of international broadcast standards.
When the surround to stereo downmix
function is active the path from the left (L)
input channel to the left post-fader output
channel and the right (R) input channel to
the right post-fader output channel is maintained. A configuration choice allows the
level of the L and R inputs routed to the L
and R outputs to be selected. By default,
when the surround to stereo downmix function is active the level of the L and R inputs
remain at unity, with no gain or loss applied.
An alternate setting allows the level of
L and R input channels to be reduced
Model 760-03/77 User Guide
Studio Technologies, Inc.
(attenuated) by 3 dB. (The available changes in signal level can also be notated as
0 dB or –3 dB.)
When the surround to stereo downmix
function is active the left surround (LS) input is routed to the left (L) post-fader monitor outputs; the right surround (RS) input
is routed to the right (R) post-fader monitor outputs. By default the level of the LS
and RS signals routed to L and R will be
reduced (attenuated) by 3 dB. An alternate
setting allows the levels to be reduced by
6 dB. (These settings can also be notated
as –3 dB and –6 dB.)
When the surround to stereo downmix
function is active the center (C) input is
routed to both the left (L) and right (R)
post-fader monitor outputs. By default the
level of the C signal routed to L and R will
be reduced (attenuated) by 6 dB. An alternate setting allows the attenuation level to
be 3 dB. (These levels can also be notated
as –3 dB and –6 dB.)
By default, when the surround to stereo
downmix function is active the LFE channel associated with a surround input is
fully attenuated (muted). This removes
LFE content from the “downmixed” signal.
In most applications this is appropriate.
However, for special situations a configuration mode allows the LFE channel to be
reduced by 6 dB and routed to both the
left (L) and right (R) post-fader monitor
outputs.
A last word on configuring the surround to
stereo downmix function: no matter what
choices are made when the function is active the center (C), left surround (LS), right
surround (RS), and subwoofer (SUB) postfader monitor outputs will fully mute.
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Pre-Fader Surround Digital
Monitor Output Mode
Post-Fader Digital and Analog
Monitor Output Level Offsets
The pre-fader surround digital monitor
output can be configured as to its place
in the Model 760-03’s signal flow. The
choices are pre- or post-downmix. In the
pre-downmix mode the digital monitor
output channels will not be impacted by
the state of the downmix functions. This
setting would be appropriate if the prefader surround digital monitor outputs were
being routed to a storage system, routed to
another facility, etc. In this case the action
of a user enabling or disabling the downmix functions won’t impact the pre-fader
surround digital monitor output signals. If
the post-downmix mode is selected the
pre-fader surround digital monitor outputs
will reflect the actions of the downmix functions. This choice would be correct if, for
example, level meters were connected to
the pre-fader surround digital monitor outputs. In this scenario a user would want to
visually observe the actions that the downmix functions impart on the signals.
To provide assistance during room calibration, the relative output levels of the
post-fader surround and stereo digital and
analog monitor output channels can be adjusted over a limited range. The eight channels can be adjusted in 0.5-dB steps over
a ±12-dB range. During configuration the
displayed value represents the dB level difference as compared to the nominal output
level. In most cases one surround and one
stereo channel should serve as the overall
reference level and not be changed. This
is typically the center channel for surround
and the left channel for stereo. The configured output level offset values apply to
both the digital and analog surround stereo
monitor outputs. It is not possible to configure a specific channel’s digital and analog
monitor output level offsets to independent
values.
Channel Pop Solo Mode
Offset Levels
Two parameters can be configured that determine how the channel pop solo function
will impact the output levels of the postfader digital and analog monitor outputs.
The up offset level sets the amount of
increase (gain) that a channel will experience when it is soloed in the channel pop
solo mode. The down offset level sets the
amount of decrease (attenuation) that the
non-soloed channels will experience when
a channel is active in the channel pop solo
mode. Refer to Figure 11 for details.
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This feature is provided primarily for use
when the post-fader monitor output channels are connected to loudspeaker systems that don’t offer a means of “trimming”
the input sensitivity of individual channels.
Without this capability, minor adjustments
to the output level of specific loudspeakers
to account for room acoustics wouldn’t be
possible.
It’s also possible to use the StudioComm’s
output level offset capability to adjust the
overall post-fader monitor output levels to
allow matching to the input sensitivity of
loudspeaker systems. In this case all the
channels (six for surround, two for stereo)
would be configured to have the same
output level offset setting. For example, the
six surround channels could all be configured to have a –3.5 dB output level offset.
However, great care must be taken when
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
configuring a system in this manner. The
dynamic range or noise floor of the audio
signals will be impacted and extreme settings could lead to poor monitor system
performance.
Restore Factory Defaults
The restore factory defaults function is provided primarily for factory use. In this way
a system can be shipped with the default
settings selected. While you are welcome
to use this function, be careful so that your
configuration efforts aren’t wasted. Specifically, be aware that the reference level
is reset to minimum level. All the other
parameters are fairly easy to set up, but
resetting the reference level would require
getting out an SPL meter and a calibrated
signal source. This is a hassle you may not
need!
Model 71 Control Console
Configuration
Two configuration choices are available on
each Model 71. One is its device address,
the other is the button disable mode. A
small button is located on the back of each
Model 71 Control Console, adjacent to the
9-pin female D-sub connector. Pressing
and holding this button for two seconds
places this specific unit in its configuration mode; normal operation of the Model
760-03 and other connected Model 71
and Model 77 units will continue. When a
Model 71 enters its configuration mode
its three LEDs will no longer perform their
usual functions. Instead the status LED will
blink to indicate that configuration mode is
active. Refer to Figure 9 for details.
Device Address
The dim and reference level LEDs will
display the Model 71’s current device
Model 760-03/77 User Guide
Studio Technologies, Inc.
Figure 9. Model 71 Control Console Front and
Back Panels
address. The rotary level control is used
to select the desired device address; the
LEDs will respond accordingly. The device
address must be selected so as not to conflict with the device address of any other
connected Model 71 or Model 77 Control
Console. The choices are A1, A2, A3,
and A4. All Model 71 units have a default
device address of A4; Model 77’s units
have a default device address of A1. This
ensures that, in most cases, no change
will have to be made. Refer to Figure 10
for details.
Button Disable
To disable the Model 71’s buttons, simultaneously press and hold both the dim and
reference buttons for two seconds. When
the disable request has been recognized
the LEDs above both buttons will flash
rapidly. Release the buttons and they will
no longer enable or disable their normal
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Address
Dim LED
Reference Level LED
A1
OFF
OFF
A2
OFF
ON
A3
ON
OFF
A4
ON
ON
Figure 10. Model 71 Device Address Chart
functions. To return the buttons to normal
operation simultaneously press and hold
both buttons for two seconds at which time
the two LEDs will flash rapidly.
To leave the configuration mode and return
a Model 71 to normal operation requires
one last action: again press and hold its
configuration button for two seconds. The
selected configuration parameters will be
stored in a nonvolatile memory device that
is located inside this specific Model 71.
Issue 4, October 2016
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Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
Configuration—Entering and Exiting Configuration Mode
and hold the configuration
 Press
button for 2 seconds to enter or
exit the configuration mode.
These LEDs will light alternately
when configuration mode is active.
Model 760-03/77 User Guide
Studio Technologies, Inc.
Issue 4, October 2016
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Configuration—Model 77 Device Address, Stereo Input C
Sample Rate Converter, and Post-Fader Stereo Monitor Output

Press and hold the Mute/Solo
button to display and configure the
Model 77’s device address, stereo
input C sample rate converter, and
post-fader stereo monitor output.
This LED displays the configuration of the
stereo input C sample rate converter
(SRC). LED not lit means SRC is disabled;
LED lit means SRC enabled. Use the button
to change the configuration.
These LEDs display the status of the post-fader stereo
monitor output function. When LED Surround is lit the
function cannot be enabled. When LED Stereo is lit the
function can be enabled. Use the button to change the
configuration.
Use the Level control to change this
specific Model 77’s device address.
Address can be either A1, A2, A3, or A4.
See Note below.
Default:
Device address A1.
Stereo input C sample rate converter enabled.
Post-fader stereo monitor output can be enabled.
Note:
The Model 77’s device address is the only parameter stored in the Model 77. All other parameters are stored
in the Model 760-03.
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Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
Configuration—Bass Management and Mute/Solo Bass
Management Mode
This LED displays the configuration of
the surround output bass management.
LED lit means surround output bass
management enabled; LED not lit means
surround output bass management
disabled. Use the button to change
the configuration. See Note below.
This LED displays the configuration of
the stereo output bass management.
LED lit means stereo output bass
management enabled; LED not lit
means stereo output bass management
disabled. Use the button to change
the configuration. See Note below.
Use these
buttons to select
bass management low-pass
filter slope.
LED Surround A
lit means
24 dB-per-octave;
LED Surround B
lit means
12 dB-per-octave.
This LED displays
the configuration
of the mute/solo
bass management mode. LED
lit means mute/
solo functions
occur post-bass
management;
LED not lit means
mute/solo functions occur prebass management.
Use the button
to change the
configuration.
Use these
buttons to select
bass management high-pass
filter slope.
LED Stereo A
lit means
24 dB-per-octave;
LED Stereo B
lit means
12 dB-per-octave.

Press and hold the Stereo C button
to display and configure the bass
management and mute/solo bass
management mode settings.
Use the Level control to select the
bass management crossover
frequency. Choices are 40, 50,
60, or 80 Hz.
Default:
Surround output bass management disabled.
Stereo output bass management disabled.
Bass management low-pass filter slope 24 dB-per-octave.
Bass management high-pass filter slope 24 dB-per-octave.
Bass management crossover frequency 80 Hz.
Mute/solo pre-bass management mode.
Note:
Bass management capability only available at sample rates of 44.1, 48, 88.2, and 96 kHz.
Model 760-03/77 User Guide
Studio Technologies, Inc.
Issue 4, October 2016
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Configuration—Sync Source, Sync Input Termination, and
Audio-Synced-to-Video Sample Rate
This LED displays the configuration of the sync input termination.
LED not lit means sync input is not terminated; LED lit means terminated with 75 ohms. Use the button to change the configuration.

Use these buttons
to select the sync
source.
LED Surround B
lit means sync
input, video;
LED Stereo A lit
means sync input,
DARS;
LED Stereo B lit
means sync input,
word clock;
LED Stereo C
lit means L/R of
currently selected
input.
Press and hold
the Stereo to
Mono button to display
and select the
sync source,
sync input
termination, and
audio-syncedto-video-sample
rate.
Use the level control to adjust the audiosynced-to-video sample rate. Available
sample rates are 32, 44.1, 48, 88.2, 96,
176.4, and 192 kHz.
Default:
Sync source is L/R of currently selected input.
Sync input terminated.
Audio-synced-to-video sample rate 48 kHz.
Issue 4, October 2016
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Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
Configuration—Reference Level
and hold the Reference Level button for 5 seconds to take a “snapshot”
 Press
of the level control’s setting at the time configuration mode was entered. The
Reference Level LED will flash when the button is initially pressed and then
light steadily when the “snapshot” has been taken. See Note below.
Default:
Reference level set for –60.0 dB post-fader monitor output level.
Note:
The 5-second button-press delay is a safety feature ensuring that the reference level will not be accidently
changed. To permanently store the new value, you must still exit the configuration mode.
Model 760-03/77 User Guide
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Issue 4, October 2016
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Configuration—Overall Display Mode, Reference Level
in dB SPL, and Auto Reference Level Off
When the Mute All button is pressed, use the Channel Mute/Solo
L and R buttons to select the overall display mode. LED L lit
means attenuation mode is selected; LED R lit means SPL mode
is selected. Use the buttons to change the configuration.
When the Mute
All button is
pressed, use the
Reference Level
button to enable
or disable auto
reference level
off. When the
Reference Level
LED is lit auto
reference level
off is enabled.
Press and hold the Mute All button to
 display
and set the overall display mode,
the reference level in dB SPL, and auto
reference level off.
Default:
When the Mute All button is pressed,
use the Level control to adjust the
reference level in dB SPL.
Attenuation display mode selected.
85.0 dB SPL reference level.
Auto ref level off disabled.
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Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
Configuration—Dim Level, Remote Mute All, and Remote Dim
This LED displays the configuration of
remote mute all. LED not lit means
remote mute all is disabled; LED lit
means enabled. Use the button to
change the configuration.
This LED displays the configuration
of remote dim. LED not lit means
remote dim is disabled; LED lit
means enabled. Use the button to
change the configuration.
Use these buttons
to select dim level.
LED Surround B lit
means –10 dB;
LED Stereo A lit
means –15 dB;
LED Stereo B lit
means –20 dB;
LED Stereo C lit
means –25 dB.
and hold the Dim button to
 Press
display and select the dim level,
remote mute all, and remote dim.
Default:
–20 dB dim level.
Remote mute all enabled.
Remote dim enabled.
Model 760-03/77 User Guide
Studio Technologies, Inc.
Issue 4, October 2016
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for Surround
Configuration—Surround to Stereo Downmix Levels and
Pre-Fader Surround Monitor Output Mode
These LEDs display the configuration of
the pre-fader surround monitor output
mode. LED L lit means output channels
are pre-downmix; LED R lit means output
channels are post-downmix. Use the
buttons to change the configuration.
Use this button to select the
level change for the LFE
channel when the surround
to stereo downmix function
is active. LED not lit means
full attenuation; LED lit means
–6 dB.
Use these buttons to select
the level change for the
center channel when the
surround to stereo downmix function is active.
LED LS lit means –3 dB;
LED RS lit means –6 dB.
Use these buttons
to select the level
change for the left
and right channels
when the surround
to stereo downmix
function is active.
LED Surround A
lit means 0 dB;
LED Surround B
lit means –3 dB.

Press and hold
the Surround to
Stereo button
to display and
confirm the
surround to
stereo downmix
levels and prefader surround
monitor output
mode.
Use these buttons
to select the level
change for the left
surround and right
surround channels
when the surround
to stereo downmix
function is active.
LED Stereo A
lit means –3 dB;
LED Stereo B
lit means –6 dB.
Default:
L and R channel level change 0 dB when surround to stereo downmix function active.
LS and RS channel level change –3 dB when surround to stereo downmix function active.
C channel level change –6 dB when surround to stereo downmix function active.
LFE level change full attenuation when surround to stereo downmix function active.
Pre-fader surround monitor outputs pre-downmix.
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Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
Configuration—Channel Pop Solo Mode Offset Levels

Press and hold
the Surround A
button to display
and select the
channel pop solo
up offset level.

Press and hold
the Surround B
button to display
and select the
channel pop solo
down offset level.
When the Surround A button is pressed, use the level
control to adjust the channel pop solo up offset level.
The range is 0.0 to 12.0 in 0.5-dB steps.
When the Surround B button is pressed, use the level
control to adjust the channel pop solo down offset level.
The range is –0.0 to –12.0 in 0.5-dB steps and full mute.
Full mute is selected by adjusting the level control past
–12.0, at which point the display will show – – – –.
Default:
6.0 dB channel pop solo up offset level.
–6.0 dB channel pop solo down offset level.
Model 760-03/77 User Guide
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Issue 4, October 2016
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for Surround
Configuration—Input Delay Settings

Press and hold the
Stereo A button to
display and select
input delay A.

Press and hold the
Stereo B button to
display and select
input delay B.
Use the level control to adjust the input delay.
Range is from 0 to 340. The display shows
delay in milliseconds at 48 kHz sampling
rate. The value is scaled up or down for other
sample rates.
Default:
Input delay 0 ms for both A and B.
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Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
Configuration—Post-Fader Monitor Output Level Offsets

Press and hold
the L button
to configure
the surround L
level offset.

Press and hold
the R button
to configure
the surround R
level offset.

Press and hold
the C button to
configure the
surround C
level offset.

Press and hold
the LFE button
to configure the
surround SUB
level offset.

Press and hold
the LS button to
configure the
surround LS
level offset.

Press and hold
the RS button
to configure the
surround RS
level offset.

Press and hold both
the L and Surround/
Stereo buttons to
configure the stereo
L level offset.
Press and hold
both the R and
Surround/Stereo
buttons to configure
the stereo R level
offset.
Use the level control to adjust the post-fader monitor output
level offsets. The range is –12.0 to 12.0 in 0.5-dB steps.
Default:
0.0 dB post-fader surround monitor output level offsets.
0.0 dB post-fader stereo monitor output level offsets.
Model 760-03/77 User Guide
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Issue 4, October 2016
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for Surround
Configuration—Restore Factory Defaults
and hold both the Surround/Stereo and Dim buttons for 5 seconds
 Press
to restore Model 77 factory defaults. Once defaults have been restored,
the associated LEDs will light. After the buttons are released, configuration
mode will be exited and normal operation will resume. See Note below.
Factory Defaults:
Device address A1.
Stereo input C sample rate converter enabled.
Post-fader stereo monitor outputs can be enabled.
Surround output bass management disabled.
Stereo output bass management disabled.
Bass management low-pass filter slope 24 dB-per-octave.
Bass management high-pass filter slope 24 dB-per-octave.
Bass management crossover frequency 80 Hz.
Mute/solo pre-bass management mode.
Sync source is L/R of currently selected input.
Sync input terminated.
Audio-synced-to-video sample rate 48 kHz.
Reference level set for –60.0 dB post-fader monitor
output level.
Attenuation display mode selected.
85.0 dB SPL reference level.
Auto reference level off disabled.
–20 dB dim level.
Remote mute all enabled.
Remote dim enabled.
L and R channel level change 0 dB when surround to
stereo downmix function active.
LS and RS channel level change –3 dB when surround to
stereo downmix function active.
C channel level change –6 dB when surround to stereo
downmix function active.
LFE level change full attenuation when surround to stereo
downmix function active.
Pre-fader surround monitor outputs pre-downmix.
6.0 dB channel pop solo up offset level.
–6.0 dB channel pop solo down offset level.
Input delay 0 ms for both A and B.
0.0 dB post-fader surround monitor output level offsets.
0.0 dB post-fader stereo monitor output level offsets.
Warning: Each Model 77 unit must have a unique address. Restoring factory defaults will reset only this specific
Model 77 to device address A1. If another connected unit is already configured for address A1, normal system
operation will stop.
Note:
The 5-second button-press delay is a safety feature ensuring that the factory defaults will not be accidently
restored.
Issue 4, October 2016
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Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
Operation
Now that you’ve installed and configured
the system, you’re ready to go. You should
find operation very easy. However, taking
time to study this section of the user guide
may prove valuable.
Upon AC mains power up the system
will return to the last operating condition,
including the selected source, downmix
modes, etc. As a precaution, however, the
post-fader surround and stereo digital and
analog monitor output levels will always
return to their minimum value. The rotary
level control or the reference level button
must then be used to return the system to
the desired monitor output level.
Model 760-03 Central
Controller
The Model 760-03’s front panel contains
two LEDs. The control console status
LED will light whenever the Model 760-03
is communicating with the one or more
connected Model 77 or Model 71 units. A
flashing control console status LED will indicate that the DC power output supporting
the control consoles is in a short circuit or
over-current condition. The control console
status LED will not light when a Model 77
is in the configuration mode or when the
Model 77 is going through its power-up
sequence.
The sync status LED will light whenever
a valid timing reference signal is being
received by the Model 760-03. A flashing
sync status LED indicates that a valid sync
signal is not being received.
Control Consoles
StudioComm for Surround operation is
controlled using the up to four Model 77
Model 760-03/77 User Guide
Studio Technologies, Inc.
or Model 71 Control Consoles that have
been connected. Two system functions can
also be controlled by means of the remote
control inputs.
Model 77 Control Console
To make things easy to describe, the Model 77’s operator functions are divided into
six main groups: input source selection,
downmix, monitor output general functions,
channel mute/solo, display and display
mode, and remote control inputs.
Any change made to any one Model 77
unit will be reflected in the LEDs and displays on all the connected units. Note that
all control consoles function simultaneously—there is no priority of one unit over
the others.
Input Source Selection
To select an input source press one of the
five input source buttons. The corresponding LED will light to indicate that the input
has been selected. Typically, only one
source will be selected for monitoring at
any one time. However, input stereo C can
be selected by itself, or mixed (summed)
with one of the other four inputs. To accomplish this is easy: simply press and hold
input stereo C then press the button associated with the other desired input source.
The two corresponding LEDs will light.
Alternately, press and hold the first desired
input (other than input stereo C) and then
press the input stereo C button.
It’s possible (although unlikely) that selecting an input will result in the mute all
function being enabled and an Err3 message being displayed. This would indicate
a conflict between the sample rate of the
selected input source and the bass management function. (Operation of the bass
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management function requires the source
to have a sample rate of 44.1, 48, 88.2, or
96 kHz.) Selecting a source with a sample
rate of 44.1, 48, 88.2, or 96 kHz will resolve the issue and normal operation will
resume. Refer to the Technical Notes section of this user guide for additional details.
Downmix
Two downmix functions allow users to perform “real-world” audio format compatibility
checks. One function allows a surround
(5.1) signal to be “folded down” (mixed) to
stereo. The other allows a stereo signal to
be converted to mono. Using the downmix
functions simply requires pressing the desired button. The buttons are set to always
“latch” the functions on and off. An LED is
located adjacent to each button and lights
whenever its respective function is active.
The downmix functions always impact the
post-fader surround and stereo digital and
analog monitor outputs. And, depending on
the selected configuration, they may also
impact the pre-fader surround digital monitor output.
A specific downmix function can only be
enabled when it is applicable for the currently selected input source. This means
that the surround to stereo downmix function can only be enabled when surround
input A or B is selected.
The Model 77 associates the state of the
downmix functions with the currently selected input. For example, if surround input
A is the selected input source and the surround to stereo downmix function is enabled, this condition will be “remembered”
when switching to one of the stereo input
sources. Upon returning to surround input
A, the surround to stereo downmix function
will again become active. For details on the
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exact actions performed by the downmix
functions refer to Appendix C at the end of
this user guide.
Surround to Stereo
When the surround to stereo downmix
function is enabled the LS, RS, and C
channels associated with a surround
source are combined (“folded down”) with
the L and R signals to create a 2-channel
stereo (left and right) signal. And, depending on the system’s configuration, the LFE
channel may also be combined with the L
and R signals. The resulting stereo signal, sometimes known as LtRt, is routed
to the L and R post-fader surround digital and analog monitor output channels.
Also, whenever the surround to stereo
downmix function is enabled the C, LS,
RS, and SUB digital and analog monitor
output channels are muted. By utilizing this
downmix function phase relationships and
inter-channel level issues can be quickly
observed.
Stereo to Mono
The stereo to mono downmix function
combines the L and R audio channels to
create a single-channel monaural signal.
This signal is sent out the C surround
digital and analog monitor output channels
while the L, R, LS, RS, and SUB digital
and analog monitor output channels are
muted.
When a surround source has been selected for monitoring, the surround to stereo
downmix function will automatically enable
whenever the stereo to mono downmix
function is enabled. This ensures that a
user will hear a mono signal created by
folding down all channels associated with
the selected surround input.
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
Monitor Output General
Functions
Four buttons and one rotary control are
associated with the post-fader digital and
analog surround and stereo monitor output
functions. The buttons control operation of
the surround and stereo outputs, reference
level, mute all, and dim functions. The rotary level control is used to manually set the
post-fader surround and stereo digital and
analog monitor output levels. These buttons and the rotary control do not impact
the pre-fader surround and stereo input C
direct digital monitor outputs.
Surround and Stereo Digital and Analog
Outputs
The surround/stereo function allows selection between two different loudspeaker
systems. When the surround output is
selected the six post-fader surround channels associated with both the digital and
analog monitor outputs are active. The
channels associated with the post-fader
digital and analog stereo monitor outputs
are muted. When the stereo output is
selected the left (L) and right (R) channels
associated with both the post-fader digital
and analog stereo monitor outputs become
active; the six channels associated with
the post-fader surround digital and analog
monitor outputs mute.
Remember that the Model 77 Control
Console can be configured to disable the
surround/stereo button. If the button is
pressed and the post-fader stereo monitor
outputs are not selected, this must be the
case!
Display Current Sample Rate
The surround/stereo monitor output select
button is also used to display the system’s
Model 760-03/77 User Guide
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current sample rate value. Pressing and
holding the surround/stereo button will
cause the current sample rate value to
be displayed: 32.0, 44.1, 48.0, 88.2, 96.0,
176.4, or 192.0. This can be useful during
troubleshooting or just for general interest.
Once the button is released normal display
operation will resume.
Reference Level
The reference level button sets the postfader surround and stereo digital and
analog monitor output levels to a preset
value. Technical personnel, using a soundpressure-level (SPL) meter and precision
signal source, should have set this level
to meet the requirements of the specific
monitoring environment. The LED associated with the reference level button will
light whenever the function is active. The
4-digit display will indicate the reference
output level. Note that the system’s default
reference level is –60.0 dB so “out of the
box” the Model 77 will display –60.0 when
reference level mode is enabled.
How the rotary level control functions
whenever the reference level mode is active depends on a configuration setting.
If the auto reference level off function is
disabled turning the rotary level control will
have no impact on the reference level function; it will remain active. If the auto reference level off function has been enabled
turning the rotary level control will cause
the reference level function to automatically turn off.
The LED associated with the reference
level button can also serve as a calibration aid. If the reference level mode is not
active, whenever the post-fader surround
or stereo digital and analog monitor output levels are precisely the same as that
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stored for the reference value the reference
level LED will flash. This exact level can be
reached through the use of the rotary level
control, either by itself or through the setting
of the rotary level control in conjunction with
the dim function. Whatever path the postfader surround and stereo monitor outputs
take to reach the reference level value, it will
cause the reference level LED to flash!
Mute All
Pressing the mute all button causes the output channels associated with the post-fader
surround and stereo monitor outputs to
mute. The 4-digit display indicates the mute
condition by showing four dashes (– – – –).
The mute all button is always set to “latch”
the function on and off. The LED associated
with the mute all button will light whenever
mute all is active. Note that if mute all is enabled via the remote mute all function, the
mute all LED will flash.
Dim
The dim function is provided for user convenience, allowing the post-fader surround
and stereo digital and analog monitor output
levels to be reduced by a fixed amount. The
Model 77’s configuration mode allows the
dim level to be selected from among four
choices: –10.0, –15.0, –20.0, or –25.0 dB.
Pressing the dim button will enable the function. The dim button is always set to “latch”
the function on and off. The 4-digit display,
when selected for output level mode, will
indicate the revised post-fader monitor output level. If the requested “dimmed” output
level is equal to or less than –96.0 dB, the
monitor outputs will go into full mute and
the display will show four dashes (– – – –).
When dim is active the post-fader monitor
output level reduction will apply no matter
whether the level is being set by the rotary
level control or by the reference level button.
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The LED associated with the dim button will
light whenever dim is active. If dim mode is
enabled via the remote dim function the dim
LED will flash.
It’s worth using a few sentences to discuss the auto dim off function. Whenever
dim is enabled due to the dim button being pressed, and the rotary level control is
active (reference level mode is not active),
changing the setting of the rotary level
control will automatically turn off dim. The
auto dim off function is a unique attempt
at protecting the aural health of users. No
longer will there be a heart-stopping blast of
audio when the dim button is pressed, supposedly to enable dim, but actually turning
dim off because it was already enabled. It’s
hard to explain unless you’ve experienced
this in person—trust us, this situation can
and does happen!
Note that the auto dim off function is not
active whenever dim is enabled due to the
remote dim function being active. This allows remote control equipment, such as a
talkback system, to reliably dim the monitor
outputs.
Rotary Level Control
The rotary level control is used to manually
adjust the post-fader surround and stereo
monitor output levels. The level control provides the ability to adjust the post-fader surround and stereo digital and analog monitor
output levels over a 70-dB range. Technically the rotary level control is a 24-step-perrevolution mechanical encoder. The amount
of level change in dB per step (“click”) will
depend on how quickly the control is turned.
When rotated slowly, each step represents
a 0.5-dB change in level. In this case, to
traverse the entire level range would require
rotating the control more than five full turns.
But the Model 77’s software detects when
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
the control is rotated more quickly and
increases the amount of level change in dB
per step. A little experimentation will allow
the user to acquire a good “feel” for how
best to use the control.
The reference level LED will flash when the
rotary level control sets the post-fader monitor output level to be the same as the stored
reference level. Whenever the rotary level
control attempts to set the output level for
less than –70.0 dB, the post-fader surround
and stereo monitor output channels will automatically mute. As previously discussed,
the 4-digit display indicates the mute condition by showing four dashes (– – – –).
If the mute all function is active the rotary
level control won’t have an impact on the
post-fader surround and stereo output levels. It’s also not active whenever the reference level function is active, except if the
auto reference level off function has been
enabled.
Channel Mute/Solo
The channel mute/solo functions allow specific channels to be selected for individual
or group mute or “solo” monitoring. The
functions impact the post-fader surround
and stereo monitor outputs, taking place
electrically “after” the input source selection,
input delay, downmix, and level control functions. The relationship between the mute/
solo function and the bass management
resources will depend on how the system
has been configured.
The mute/solo mode button and the six
channel mute/solo buttons, along with associated LEDs, work together to provide
excellent operating flexibility. The channel
mute/solo mode button allows the user to
select between the mute and solo functions.
Going from mute mode to solo mode, or
Model 760-03/77 User Guide
Studio Technologies, Inc.
vice-versa, clears all active mutes or
solos. Pressing the mode button twice
is a legitimate means of quickly clearing
muted or soloed channels. To mute or solo
a channel simply requires pressing one of
the channel mute/solo buttons. The buttons
function in a press-to-enable/press-to-disable “latching” mode. Multiple channels can
be muted or soloed at the same time. The
LED associated with any muted or soloed
channels is used to indicate that the function is active.
In most cases the mute/solo function will
be configured to act in a pre-bass management signal flow, creating an “input” mute/
solo function. In this case soloing one channel when bass management is enabled will
result in audio content being reproduced
in both the soloed channel as well as the
subwoofer post-fader monitor output channels. Should the function be configured for
post-bass management mode soloing a
channel will result in only that specific monitor output channel reproducing the audio
content.
Selecting the Solo Mode
As previously discussed in this user guide,
solo operation can be selected between
normal and channel pop. When the normal solo mode has been enabled the solo
LED will light steadily. When the channel
pop solo mode is enabled the solo LED will
flash. It’s easy to change from normal to
pop solo, and vice-versa. Simply press and
hold the mode button and use the surround
to stereo button to select the desired solo
mode. The LED associated with the surround to stereo button displays the active
mode. Refer to Figure 11 for details. The
selected mode will be stored in non-volatile
memory so a power-down/power-up cycle
will not change the selection.
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
During normal operation, press and hold the Mute/Solo button
to view and change the solo mode and input delay settings.
This LED displays the current setting
of the solo mode. LED not lit means
normal; LED lit means channel pop.
Press the button to change the mode.
This LED displays the current
setting of the input delay.
LED not lit means input delay A
is selected; LED lit means input
delay B is selected. Press the
button to change the setting.
The display shows the currently
selected input delay in milliseconds.
Figure 11. Solo mode and input delay settings
Input Delay
Two input delay settings, A and B, can be
selected and saved during system configuration. These are provided for aligning the
audio input signals with latencies associated with video processing and display
systems. During normal operation of the
StudioComm system the active input delay, A or B, can be selected. The channel
mute/solo button, stereo to mono button,
and 4-digit display are used to display and
select the input delay. When the mute/solo
button is pressed and held the LED associated with the stereo to mono button indicates whether input delay A or input delay
B is active. The 4-digit display will show
the active delay time in milliseconds. While
pressing and holding the mute/solo button
the stereo to mono button can be pressed
to change the selected input delay. Refer
to Figure 11 for details. The selected input
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delay will be stored in non-volatile memory
so a power-down/power-up cycle will not
change the selection.
Display and Display Mode
The Model 77’s 4-digit LED display shows
the post-fader surround and stereo digital
and analog monitor output levels as either
the amount of attenuation or the sound
pressure level (SPL). Both will indicate
level in dB. What the digits actually represent will depend upon how the Model 77
has been configured.
Display in dB of Attenuation
If configured for the attenuation mode
the display will show the post-fader monitor output level as an attenuation value in
reference to the maximum output. This is
in the form of 0.5-dB steps less than the
maximum of 0.0 dB. So a display of –40.5
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
would indicate that the surround or stereo
monitor output is set to be 40.5 dB below
the maximum level. As the rotary level control is moved counterclockwise the output
level will go down and the indicated value
will get more negative.
Display in dB SPL
If the Model 77 is configured to display the
post-fader digital and analog monitor output level in dB SPL, the 4-digit display will
always show the output level in positive
numbers. These numbers are intended to
represent the sound pressure level in dB
SPL, a figure that should directly relate to
the actual sound pressure level that the surround or stereo loudspeaker system is presenting to users. (Typically, the level value
would actually be in dBC, the C-weighted
sound pressure level.) When the reference
level button is enabled, or the rotary level
control is set so that the reference level
has been reached, the display will typically
show something in the range of 82 to 87 dB.
Assuming that the monitoring environment
has been correctly calibrated, this would
indicate that an average listening level of
85 dB, for example, had been achieved.
Channel Pop Solo Display
As has been previously discussed, the
channel pop solo mode offers a unique way
of sonically highlighting an individual channel. A channel selected for soloing in this
mode will have its level increased while the
other non-soloed channels will be reduced
in level. To highlight this condition the letters POP will appear in the 4-digit display
whenever a channel is actively being soloed
in the channel pop solo mode. This ensures
that a user will understand that the post-fader monitor outputs no longer represent the
true inter-channel level relationships.
Model 760-03/77 User Guide
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Remote Control Inputs
As previously discussed in the Installation section of this user guide, two remote
control signals can be connected to the
Model 760-03 and then configured for
operation. The functions are remote mute
all and remote dim. When an external
signal activates remote mute all the LED
on the Model 77 associated with the mute
all button will flash. If mute all was already
active when the remote mute all function is
activated, the LED will change from being
steadily lit to flashing.
When an external signal activates remote
dim the LED on the Model 77 associated
with the dim button will flash. If dim was already active when remote dim is activated,
the LED will change from being steadily lit
to flashing.
Model 71 Control Console
The Model 71 Control Console provides a
rotary level control and a limited number of
pushbutton switches and LEDs for control
and status display. The rotary level control
allows adjustment of the post-fader surround and stereo monitor output levels.
Two buttons, along with associated LEDs,
provide access to the dim and reference
level functions. A status LED lights steadily
whenever normal Model 71 operation is
taking place.
Any changes made using the Model 71’s
rotary level control and buttons will be
reflected in the appropriate LEDs and displays on all the connected Model 77 and
Model 71 units. And, as expected, changes
made using a Model 77 will be reflected in
the Model 71’s LEDs.
In some applications it may be desirable to
disable operation of a Model 71’s dim and
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reference buttons. An example could be
where non-technical personnel are allowed
only to use the rotary level control. A configuration parameter, previously described
in the Model 71 Control Console Configuration section, allows button operation to
be disabled.
Rotary Level Control
The rotary level control is used to manually
adjust the post-fader surround and stereo
monitor output levels. Its operating characteristics are identical to those of the Model
77 Control Console, discussed earlier in
this section.
Dim
The dim function allows the post-fader surround and stereo monitor output levels to
be reduced by a fixed amount. Its operating characteristics are identical to those of
the Model 77 Control Console, discussed
earlier in this section.
An indication is provided should the dim
button be pressed when button operation
has been disabled. Its associated LED will
flash briefly but no operating change will
occur. The LED will continue to display the
status of the dim function as selected by
other Model 77 and Model 71 units.
Reference Level
The reference level button sets the postfader surround and stereo monitor output
levels to their preset values. The operating characteristics are identical to those of
the Model 77 Control Console, discussed
earlier in this section.
An indication is provided should the reference button be pressed when button
operation has been disabled. The associated LED will flash briefly but no operating
Issue 4, October 2016
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change will occur. The LED will continue
to display the status of the reference level
function as selected by other Model 77 and
Model 71 units.
Technical Notes
Loss of Sync
The Model 760-03 relies on an external timing reference (sync) source for proper operation. This can be in the form of an AES3,
word clock, DARS (AES11), bi-level video,
or tri-level video reference signal. In most
cases the sync signal will be connected to
the sync input BNC connector located on
the Model 760-03’s back panel. Alternately,
a configuration choice allows the L/R input
of the AES3 source currently selected for
monitoring to also serve as the system’s
timing reference. Whenever a valid sync
signal has been connected to the Model
760-03 the sync status LED, located on the
unit’s front panel, will light. The sample rate
of the monitor output channels will reflect
the rate of the sync input and, if a video
sync source is utilized, the configured rate.
If a valid sync signal is not present several
visual indications are provided. On the Model 760-03 the sync status LED will flash. On
all connected Model 77 Control Consoles
the 4-digit LED display will cease normal
operation, instead alternating between the
words no and sync. When a valid sync
signal is again connected the Model 76003’s sync status LED will light steadily. On
the Model 77 units the word sync will momentarily be displayed followed by a brief
display of the monitor output sample rate.
The sample rate will display as 32.0, 44.1,
48.0, 88.2, 96.0, 176.4, or 192.0, reflecting
the impact of the sync source rate and the
Model 760-03’s configuration.
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
If during normal operation the sync source
changes from one valid rate to another a
visual indication is provided. On the Model
77 units the new sample rate—32.0, 44.1,
48.0, 88.2, 96.0, 176.4, or 192.0—will momentarily be displayed.
Any time that a valid sync signal is not
connected to the Model 760-03 the digital
monitor output will automatically revert
to an internally generated sample rate of
48 kHz with no digital audio content present. This audio “black” signal will allow most
connected equipment to continue to function correctly, of course with no meaningful
audio signal present. As soon as a valid
sync signal is again connected to the Model
760-03 the monitor outputs will automatically switch to their correct sample rate and
audio signals will again be present.
Power Down
Great care was taken in the Model 760-03’s
design to minimize the chance that clicks,
pops, or other objectionable audio signals
will be present on the post-fader digital
and analog monitor outputs. A power-down
circuit supplies the main microcontroller
integrated circuit with an indication that a
power loss is imminent. When this condition is detected the digital monitor outputs
will switch to silence (digital audio “black”)
in preparation for a complete loss of signal.
Electromechanical relays associated with
the analog monitor outputs will change to
their mute state to minimize the chance of
signal transients reaching the connected
loudspeaker inputs.
Power-Up Messages
Upon mains power being applied to the
Model 760-03 all connected Model 77
units will go through a power-up sequence.
Model 760-03/77 User Guide
Studio Technologies, Inc.
The sequence starts by each of the individual LEDs lighting in a “walk-through”
sequence. Then the 4-digit display tests all
its LED segments. Finally, a set of messages provide details on the specific Model
77 and connected Model 760-03 software
versions:
1. Displays 77
2. Displays Model 77’s software version
3. Displays Model 77’s unit address
(A1, A2, A3, or A4)
4. Displays 760
5. Displays Model 760-03’s main
software version
6. Displays FPgA
7. Displays Model 760-03’s logic
device (FPGA) software version
After a successful system power-up
sequence normal operation will then
commence.
Error Codes
Should a problem be encountered during
power up one of four error codes may
show on the Model 77’s 4-digit display.
Error Code Err1
Err1 indicates that communication is not
taking place between the Model 77 and the
Model 760-03. The most likely cause would
be incorrect wiring of the data pair linking
the two units.
Error Code Err2
Err2 indicates that the Model 760-03 is
having problems with its internal logic
device. (A high-speed field-programmable
gate array (FPGA) serves as the digital
“heart” of the Model 760-03 and without
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for Surround
it no audio activity can occur.) The only
way to remedy this condition is to first try
removing and reconnecting mains power.
(And that’s a long-shot as to whether
it would accomplish anything.) If Err2 continues to be displayed the Model 760-03
must be returned to the factory for service.
Error Code Err3
If a digital audio source with a sample rate
of other than 44.1, 48, 88.2, or 96 kHz is
connected Err3 will display and the mute
all function will be automatically enabled.
In this scenario, selecting a different source
that has a sample rate of 44.1, 48, 88.2,
or 96 kHz will return the system to normal
operation.
Error Code Err4
Err4 will display if communications with
a central controller has been established
but that specific central controller is not
compatible with the Model 77. For example,
Err4 will display if a Model 77 has been
connected with a Model 780-Series central
controller.
Sample Rate Conversion
(SRC)
Circuitry associated with stereo input C
can provide sample rate conversion (SRC)
capability. A digital audio signal connected
to that input can have its sample rate and
timing re-synchronized to match the Model
760-03’s internal timing. While it would
be nice to proclaim that the engineers at
Studio Technologies came up with a unique
and exotic circuit to perform this function it’s
really not the case. Several semiconductor
companies provide “single-chip” SRC solutions and an excellent one from AKM was
selected for the Model 760-03. The technical capabilities of the Model 760-03’s SRC
Issue 4, October 2016
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function is stated in this way: the sample
rate of an input signal can range from 1/6
to six times the Model 760-03’s output
sample rate, with the additional restriction
that it must be no less than 8 kHz and no
more than 216 kHz. The Model 760-03’s
output sample rate is determined by the
selected timing reference (sync) signal and,
if required, a configured value. If a word
clock, DARS (AES11), or AES3 signal is
the designated sync source its rate will be
the Model 760-03’s output sample rate. If a
video sync signal is connected, the Model
760-03’s sample rate is selected as part of
the configuration process.
So in practice what can the SRC function
accomplish? If the output sample rate is
48 kHz then a signal connected to stereo
input C can have a sample rate from 8 to
216 kHz. Or, as another example, if the
Model 760-03’s output sample rate is
96 kHz a signal connected to stereo input C
can have its sample rate range from 16 to
216 kHz.
As useful as allowing one disparate sample
rate to be converted to another, it may be
the ability of the Model 760-03’s SRC function to re-synchronize a signal that proves
most valuable. For example, in typical postproduction and broadcast applications all
signals will have a sample rate of 48 kHz.
A Model 760-03 and all of its normally connected input signals will be “locked” to the
main timing reference signal that supports
the 48 kHz sampling rate. But, as an example, a signal associated with a portable
device, while at a 48 kHz sampling rate,
may not be synchronized (“genlocked”)
to the “house” reference. Connecting this
signal to stereo input C will cause the SRC
function to “lock” it to the Model 760-03’s
rate, thus allowing it to be monitored over
a loudspeaker system. In addition, the steModel 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
reo input C direct monitor output can
be connected to other devices that find
need for the now-synchronized signal. In
some cases it may be useful to connect
the stereo input C direct monitor output
to the input of a signal router, allowing an
entire facility to access the signal.
Model 760-03 to Control
Console Connections
Figure 8 gives a detailed description of
the signals that connect the Model 76003 Central Controller to the one or more
Model 77 or Model 71 Control Consoles.
The Model 760-03 provides 12 Vdc for use
by the control console’s circuitry. The DC
output is current-limited to minimize the
chance that a short-circuit condition will
damage the Model 760-03’s circuitry. An
asynchronous, bi-directional data interface
links the connected units. The RS-485
hardware connection scheme operates at
a rate of 115.2 kbit/s and uses an 8-N-1
data format. The Model 760-03 communicates with each Model 77 and Model 71
unit 20 times per second, receiving button
and rotary level control information and
sending LED and 4-digit display status
data.
“Hot” Disconnection of
Control Consoles
internal digital audio channels as well as
saving the current operating parameters.
No clicks, pops, or other noises will occur
when the Model 77 or Model 71 units are
again connected. The control consoles
will go through their standard power-up
sequence and then normal operation will
resume.
Channel Status, User, and
Validity Bits
The non-audio bits that are part of the
AES3 digital audio monitor output channel
data are actively controlled by the Model
760-03’s software. The Channel Status
bits use the Professional Use of Channel
Status block. They indicate a word length
of 24 and the current sample rate. The correct CRC is also calculated and inserted.
The User bits are always set to 0. When
a valid timing reference (sync) source is
recognized by the system the Validity bits
will be set to 1.
The Model 760-03’s hardware is capable
of routing the C/U/V bit information from
any of the L/R inputs, as well as the sync
input, to the main logic device (FPGA)
and then on to the digital audio transmitter
(DIT) integrated circuits. This is provided
for future use and is not active at this time.
There’s no problem relocating one or more
Model 77 or Model 71 Control Consoles
while the StudioComm system is operating. You can disconnect the 9-pin interconnecting cable, move the unit (or units), and
then reconnect without issue. Upon disconnection of all control consoles the Model
760-03 Central Controller will mute the
Model 760-03/77 User Guide
Studio Technologies, Inc.
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for Surround
Specifications
Model 760-03 Central Controller
General Audio:
Supported Sample Rates: 32, 44.1, 48, 88.2, 96,
176.4, and 192 kHz
Word Length: 24 bits maximum
Internal Processing: 32 bits
Input-to-Output Latency: two samples (e.g., 0.042
milliseconds @ 48 kHz sample rate)
Digital Audio Inputs: 5 (18 audio channels)
Configuration: two surround (5.1) and three stereo
Type: balanced AES3 (110 ohms, 5 Vpp)
Connector—Surround Inputs and Stereo Inputs
A & B: 25-pin female D-subminiature (DB-25F),
AES59-2012-compliant
Connector—Stereo Input C: 3-pin female XLR
Sample Rate Conversion (SRC):
Application: available on Stereo Input C
Input Sample Rate Range: 8 to 216 kHz, limited to
1/6 to 6 times the output sample rate
Latency: 1 millisecond, nominal
Sync Source: configured to follow L/R of currently
selected input or signal connected to sync input
Sync Input:
Compatible Sources: word clock, DARS (AES11),
bi-level video, tri-level video
Jitter: 4 ns pp maximum
Connector: BNC (per IEC 60169-8 Amendment 2)
Termination: 75 ohms, selectable on/off
Digital Monitor Outputs: 16 channels (8 pairs)
Configuration: organized as two surround (5.1)
and two stereo
Dynamic Range: >135 dB
Type: balanced AES3 (110 ohms, 5 Vpp)
Connector: 25-pin female D-subminiature
(DB-25F), AES59-2012-compliant
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Analog Monitor Outputs: 8
Configuration: organized as one surround (5.1)
and one stereo (2-channel)
Type: electronically balanced, source impedance
200 ohms
Nominal Level: +4 dBu @ –20 dBFS input source
and level control at maximum setting
Maximum Level: +24 dBu into 2000 (2 k) ohms or
greater
Frequency Response, Digital Inputs to Analog
Monitor Outputs: 10 Hz-20 kHz +0.0/–0.3 dB @
48 kHz sample rate; –3 dB @ 64 kHz
Distortion (THD+N): <0.002%, –1 dBFS,
20-22 kHz, 22 kHz bandwidth
S/N Ratio: 89 dB, ref +4 dBu output
Dynamic Range: >109 dB
Crosstalk: –98 dB at 1 kHz; –97 dB at 16 kHz,
ref –1 dBFS input
Connector: 25-pin female D-subminiature
(DB-25F), AES59-2012-compliant
Configurable Input Delay: 0 to 340 milliseconds @
48 kHz sample rate (scales up or down depending
on actual sample rate)
Post-Fader Monitor Output Level Offsets:
each surround and stereo channel independently
adjustable in 0.5-dB steps over a ±12-dB range.
(Digital and analog outputs associated with a
specific channel share the same setting.)
Bass Management:
Supported Sample Rates: 44.1, 48, 88.2, and
96 kHz only
Crossover Frequency and Type: –6 dB @ 40, 50,
60, or 80 Hz, symmetrical for low-pass and highpass filters, maximally flat
Filter Slope: 12-per-octave or 24 dB-per-octave
Overall Operation: independent on/off selectable
for surround and stereo post-fader monitor outputs
Downmix:
Surround to Stereo and Stereo to Mono
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
Control Console Interface:
Type: RS-485, 115.2 kbit/s, 8-1-N
Polling Interval: 80 milliseconds, nominal
Power: 12 Vdc, 500 mA maximum
Connector: 9-pin female D-subminiature (DE-9F)
Remote Control Inputs: 2
Functions: remote mute all, remote dim
Type: 3.3 Vdc logic, activates on closure to system
common
Connector: 9-pin female D-subminiature (DE-9F)
AC Mains:
Requirement: 100 to 240 V, +10/–15%, 50/60 Hz,
15 W maximum
Connector: 3-blade, IEC 320 C14-compatible
(mates with IEC 320 C13)
Dimensions:
19.00 inches wide (48.3 cm)
1.72 inches high (4.4 cm)
7.00 inches deep (17.8 cm)
Mounting: one space (1U) in a standard 19-inch
rack
Weight: 3.6 pounds (1.6 kg)
Model 77 Control Console
Application: up to four Model 77 Control Consoles can be connected to a Model 760-03 Central
Controller
Power: 12 Vdc nominal (9 Vdc minimum), maximum current 100 mA, provided by Model 760-03
Central Controller
Control Data:
Type: RS-485
Data Rate/Format: 115.2 kbit/s, 8-N-1
Connector: 9-pin female D-subminiature (DE-9F)
Dimensions (Overall):
7.20 inches wide (18.3 cm)
2.20 inches high (5.6 cm)
5.40 inches deep (13.7 cm)
Weight: 1.7 pounds (0.8 kg)
Model 71 Control Console
Application: up to three Model 71 Control Consoles can be connected to a Model 760-03 Central
Controller
Power: 12 Vdc nominal (9 Vdc minimum), maximum current 35 mA, provided by Model 760-03
Central Controller
Control Data:
Type: RS-485
Data Rate/Format: 115.2 kbit/s, 8-N-1
Connector: 9-pin female D-subminiature (DE-9F)
Dimensions (Overall):
3.20 inches wide (8.1 cm)
2.20 inches high (5.6 cm)
4.10 inches deep (10.4 cm)
Weight: 0.8 pounds (0.4 kg)
Specifications and information contained in this
User Guide subject to change without notice.
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Appendix A—Connection Pin-Out
Charts
Channel
Signal
High (+)
Signal
Low (–)
Shield
Connections
Channel
Signal
High (+)
Signal
Low (–)
Shield
Surround Input A L/R
1
24
12
25
Pre-Fader L/R
1
24
12
25
Surround Input A C/LFE
2
10
23
11
Pre-Fader C/SUB
2
10
23
11
Surround Input A LS/RS
3
21
9
22
Pre-Fader LS/RS
3
21
9
22
Stereo Input A
4
7
20
8
Stereo Input C Direct
4
7
20
8
Surround Input B L/R
5
18
6
19
Post-Fader L/R
5
18
6
19
Surround Input B C/LFE
6
4
17
5
Post-Fader C/SUB
6
4
17
5
Surround Input B LS/RS
7
15
3
16
Post-Fader LS/RS
7
15
3
16
Stereo Input B
8
1
14
2
Post-Fader Stereo
8
1
14
2
Connections
Notes: 1) All signals transformer-coupled digital audio;
balanced AES3 (110 ohms, 5 Vpp) compatible.
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.
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.
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.
Connections for Surround A, Surround B,
Stereo A, and Stereo B Digital Inputs
Connections for Digital Monitor Outputs
Connections
Signal
Pin
Channel
Signal
High (+)
Signal
Low (–)
Shield
Direction
Surround L
1
24
12
25
2
10
23
11
Data Shield
1
Shield
Surround R
Remote Mute All
5
Input
Surround C
3
21
9
22
Remote Dim
6
Input
Surround SUB
4
7
20
8
Remote Spare 1
8
Input
Surround LS
5
18
6
19
Remote Spare 2
9
Input
Surround RS
6
4
17
5
Remote Input Common
4
Common
Stereo L
7
15
3
16
Stereo R
8
1
14
2
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.
Connections for Remote Control Inputs
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.
Connections for Analog Monitor Outputs
Issue 4, October 2016
Page 52
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
Signal
Data + (RS-485)
Pin
1
Direction
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.
Connections between Model 760-03 and
Model 77 and Model 71
Model 760-03/77 User Guide
Studio Technologies, Inc.
Issue 4, October 2016
Page 53
for Surround
Appendix B—Sync Input Sources
The Model 760-03’s sync input has been tested and confirmed for correct operation with the
following sync signals:
Word Clock: Square wave signal with rate of 32, 44.1, 48, 88.2, 96, 176.4, or 192 kHz.
DARS (AES11) or AES3: Signal with sample rate of 32, 44.1, 48, 88.2, 96, 176.4, or
192 kHz.
Bi-Level and Tri-Level Video: See table below.
Video Format
Video Format, continued
NTSC (“Black Burst”)
1035i/59.98 Hz
PAL (“Black Burst”)
1035i/60 Hz
525i/59.94 Hz
1080i/50 Hz
525p/59.94 Hz
1080i/59.94 Hz
625i/50 Hz
1080i/60 Hz
625p/50 Hz
1080p/23.98 Hz
720p/23.98 Hz
1080p/24 Hz
720p/24 Hz
1080p/25 Hz
720p/25 Hz
1080p/29.97 Hz
720p/29.97 Hz
1080p/30 Hz
720p/30 Hz
1080psf/24 Hz
720p/50 Hz
1080psf/23.98 Hz
720p/59.94 Hz
720p/60 Hz
Issue 4, October 2016
Page 54
Model 760-03/77 User Guide
Studio Technologies, Inc.
for Surround
Appendix C—Downmix Formulas
The following provides a summary of the action performed when the downmix modes
are active. Signals at unity gain unless noted. 1 = 0 dB; 0.707 = –3 dB; 0.5 = –6 dB;
0.35 = –9 dB; 0 = full attenuation.
Surround to Stereo
L = (1 or 0.707)L + (0.707 or 0.5)C + (0.707 or 0.5)LS +(0 or 0.5)LFE
R = (1 or 0.707)R + (0.707 or 0.5)C + (0.707 or 0.5)RS + (0 or 0.5)LFE
C, LFE, LS, and RS monitor outputs mute
Stereo to Mono
With a stereo input selected the result is:
C = 0.707L + 0.707R
L, R, LS, RS, and LFE monitor outputs mute
With a surround input selected the surround to stereo downmix function automatically
enables resulting in:
C = (0.707 or 0.5)L + (0.707 or 0.5)R + (0.707 or 0.5)C + (0.5 or 0.35)LS
+ (0.5 or 0.35)RS + (0 or 0.5)LFE
Model 760-03/77 User Guide
Studio Technologies, Inc.
Issue 4, October 2016
Page 55
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