Distributed Vs. Centralized Audio Processing
May 13, 2013 3:40 PM, By Don Kreski
Peak Audio founders say the distributed DSP model is obsolete.
There’s a debate going on today that some audio professionals thought was settled years ago. Is it better to centralize digital signal processing in a large audio system or distribute it over many processors linked via the network?
Most sound companies today argue for distributed processing, but Rich Zwiebel and John Britton, the founders of engineering firm Peak Audio, which originated the concept of configurable audio processing back in 1992, say it’s an obsolete approach.
The biggest argument typically made for distributed processing is that it’s more reliable than centralized. If one component fails, the remainder of the system can continue to function.
Not so, says Zwiebel. “Our engineering team has done it both ways, and we know that distributed is far more problematic, because it is in so many boxes. That is, you go from a single point of failure to many points of failure, any one of which can end the event.” Yet with today’s technology, you can safely rely on a single processor, because you can back it up with a redundant DSP that takes over automatically should your primary unit develop a glitch.
The concepts behind distributed DSP
Britton and Zwiebel’s engineering team originally began working on DSP more than 20 years ago, creating the hardware and software designs for Peavey’s MediaMatrix product line. Introduced in 1992, MediaMatrix was a centralized processing platform that could use a flexible number of DSP cards in a multi-slot cardframe.
“Our original idea was to be able to support smaller installations but then get the horsepower up by adding processing cards as needed for larger systems,” Britton explains. The multi-card design proved to be very popular.
After Britton and Zwiebel’s team developed CobraNet in the mid-90s, they began thinking about putting their DSP chips into separate boxes and linking them via the network. Peak Audio finished engineering a new product, MediaMatrix Nion, in 1999, and it was even more scalable and flexible than the earlier designs. Processors could be placed throughout a facility close to input and output devices, yet still be linked for facility-wide functions such as paging. The team initially felt that system reliability might improve as well, since if any of the processors failed, the rest of the audio system could go on functioning.
In 2001, Zwiebel and Britton sold Peak Audio to Cirrus Logic and by 2006 they accepted management positions at QSC Audio. The team they organized there developed a new platform, Q-Sys, modernizing the DSP concept with all audio processing centralized in a single core. The core, based on an Intel processor, is linked to inputs and outputs via off-the-shelf gigabit network components.
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