Studio Technologies 780-02, 790 Data Sheet

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
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
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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
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