Q & A: Surround Sound Auditorium
We're designing a multipurpose auditorium that will also be used for film presentations. Our client wants to have surround sound from a DVD player at the stage and in the control booth 100 feet away, but the budget will only allow for one digital processor.
Q. We're designing a multipurpose auditorium that will also be used for film presentations. Our client wants to have surround sound from a DVD player at the stage and in the control booth 100 feet away, but the budget will only allow for one digital processor. Which digital audio format — AES-EBU, AES-3ID, SPDIF (either optical or over an RCA cable), TOSLINK, etc. — would work best for sending the signal over that distance?
A. I'd recommend using the Sony/Philips Digital Interface Format (S/PDIF), which is the consumer version of AES-3 (AES/EBU). S/PDIF requires less expensive hardware, and there are only small differences between the two protocols. Primarily used with CD players, MiniDiscs, and modern computer audio cards, the S/PDIF interface can also be used to carry compressed digital audio, such as connecting the output of a DVD player to a home theater receiver that supports Dolby Digital or DTS surround sound.
Because the distance to the control booth is less than 1,000 feet, I'd also recommend using an electrical approach versus the more expensive optical approach for sending the signal. You should select a high-quality, RG6 size, low-loss, double-shielded precision 75 ohm-coaxial cable and impedance-matched, 75-ohm RCA-type male connectors.
That may be all you need to send the signal 100 feet, but if added signal strength is necessary, I'd suggest using a low-cost repeater/amplifier such as Radio Design Labs' FP-SPR1.
— Ivan Teskey, integration manager/special systems engineer, CCS Presentation Systems, Scottsdale, AZ
Next Month's Question: I'm currently working on a sports bar project where the owner wants to install a distributed audio system with wireless audio receivers that patrons can use to select content from any TV in the bar. Is there a way to accomplish this? — Cory Plummer, president, Home A/V Solutions, Gray, ME
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