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Model 780-02 Central Controller / Model 790 Control Console
Overview
Creating and distributing eight channel (7.1) surround audio material has become
common for entertainment, cinema, and allied applications. As such, the ability to
simply and effectively monitor these sources is imperative during the recording
and post-production process. Studio Technologies has addressed these needs
with the StudioComm for Surround Model 780-02 Central Controller and the
Model 790 and Model 71 Control Consoles. With digital audio inputs, analog
monitor output, support for multiple user control surfaces, and an extensive
set of resources it’s a simple task to integrate a monitoring system into virtually
any facility. The carefully selected group of features, including two surround
(7.1) and one stereo input, configurable input-source time delay, LFE lowpass filter, analog surround (7.1) monitor output, 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 790 Control Con
sole. It’s the system’s “command center” and is designed to reside at a user’s
location, allowing fingertip selection of all monitoring functions. Numerous
LEDs provide complete status information. A 4-digit numeric display indicates
the level of the monitor output. A major strength of the Model 790 is its ability
to configure, under software control, many important operating parameters.
Intended for secondary monitoring locations that don’t require all of the Model 790’s features, 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.
Model 790
Control Console
Key Features:
• 7.1 surround and stereo balanced digital
audio inputs
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• 7.1 surround analog output
• Balanced digital audio capability
• Allows use of multiple control consoles
• Superior audio quality
Most installations will use only one Model 790 Control Console. However, up to three additional Model 790 or Model 71 Control
Consoles can also be connected. This provides multiple users with control over a facility’s monitor system. And to make instal
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lation simple, the Model 780-02 provides power for all connected Model 790 or Model 71 units.
The core of this StudioComm for Surround system is the Model 780-02 Central Controller. The one-rack-space unit contains
circuitry that supports balanced digital audio inputs, a balanced analog monitor output, digital audio and control processing,
and interfacing for the user control surface(s). The Model 780-02 provides two surround (7.1) and one 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 44.1, 48, 88.2 or 96 kHz and a bit depth of up to 24 to be supported. Circuitry
associated with the stereo input provides sample rate conversion (SRC) capability, allowing a wide range of digital audio sources
to be monitored. To compensate with processing delays (latency) associated with associated video displays up to 340 millisec
onds of input delay can be selected. For flexibility, two delay values can be configured, allowing real-time selection as desired.
A number of different signals can serve as the Model 780-02’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.
Model 780-02 Central Controller Front Panel
50393-0215, Issue 1
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Model 780-02 Central Controller Back Panel
One analog surround (7.1) monitor outputs is provided. It’s intended for connection to analog inputs on a monitor loudspeaker
system. Electrically balanced, the monitor output signals provide low-noise, low-distortion, and high-headroom performance.
A sophisticated bass management function is integral to the Model 780-02’s design and can be enabled if desired. 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 sonic “picture” of the source material from
being presented. To overcome this, the low-frequency energy from the seven channels associated with the surround inputs and
the two channels associated with the stereo input can be separated and routed to the subwoofer (SUB) channel of the monitor
output. Several of the bass management functions can be configured to match the requirements of specific installations.
Great care was taken in designing the system’s architecture, ensuring that the character of the audio input signals was preserved.
All audio processing, including bass management, is performed in 32-bit logic using a high-speed field-programmable gate array
(FPGA) integrated circuit. High-performance integrated circuits are used to perform input, output, and clocking tasks.
The Model 780-02 occupies one space (1U) in a standard 19-inch rack. Digital audio
sources are interfaced with the Model 780-02 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. Analog monitor output signal connections are made using
a 25-pin female D-subminiature connector. One 9-pin female D-subminiature connector is
used to connect the Model 780-02 with a maximum of four Model 790 or Model 71 Con
trol Consoles. A second 9-pin “D-sub” connector is used to interface with remote control
signals. AC mains power is connected directly to the Model 780-02, with an acceptable
range of 100 to 240 V, 50/60 Hz.
Additional Details
Model 71 Control Console
The Model 790 provides three buttons and associated LEDs for selection of the source to
be monitored. The choices are the two surround inputs and the stereo input; only one source can be monitored at a time. It’s
interesting to note that while the surround inputs have an LFE channel associated with them, the corresponding monitor output
channel is designated as subwoofer (SUB), rather than LFE. This terminology was 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 main channels, combine it with the contents from the LFE input channel, and route the combination to the monitor
output’s subwoofer (SUB) channel.
An LFE low-pass filter function is provided as a means of checking the audio content in the LFE channel of a selected surround
input. The user can enable and disable the function as required, helping to ensure that the proper signals are being mixed to the
LFE channel. Having the correct audio content in the LFE channel can be critical as the LFE channel is typically band-restricted
during distribution.
The level of the channels associated with the monitor output 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 monitor
output channels to automatically mute whenever the output level control reaches maximum attenuation. Using the reference level
function, the monitor output level 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, the 4-digit LED display will show the level of the monitor output channels. To match
the needs of a facility, the display can be configured to show either the attenuation level or the sound pressure level (SPL).
The dim function allows the monitor output level to be reduced by a fixed dB amount. The dim level is configured from among
four available values. A mute all function allows the monitor output channels to be simultaneously muted. The input mute/solo
section allows an input channel to be muted or monitored as desired. Multiple channels can also be simultaneously selected
for muting or “soloing.”
Studio Technologies, Inc. StudioComm 780-02/790, Issue 1, Page 2