Streaming Helps AV Industry Eliminate Cable Clutter

Besides the ability to replace digital snakes, network audio devices also leverage the inherent benefits of streaming and network protocols. Complicated routing of audio in the AV industry used to require an audio matrix—somewhat akin to the old telephone switchboards that required an audio signal from one location to be physically connected to the destination point. An audio matrix could often double the cost on a large project, but network audio devices handle the matrix issues inherently: Packets sent across the local data network can be converted back to analog or AES/EBU audio at multiple points along the data network path without imposing impedance or any of the other constraints of a traditional audio signal path.

Typical pricing for these network audio devices range from $700 (16 outputs, balanced line level) to $2,000 (16 inputs, balanced microphone level with pre-amps to boost to line level). Even though network audio devices may appear excessively priced, the combined price of end points using structured wiring has fallen below the cost of specialized cabling and labor to pull specialized cabling.

In a large installation, as noted by this example, the cost savings are clear: A 78% reduction in conduit, labor and cabling cost was achieved through the use of network audio devices, for a savings of almost $130,000. Adding in the conservative cost of a network audio device end points at $2,200 per room for 40 rooms, the total cost savings still exceeds $39,000.

There are three primary companies involved in this technology category—CirrusLogic, Digigram, and NetworkSound. All three companies provide unique chipsets (CobraNet, EtherSound, and NetworkSound/MaGIC, respectively) that can expand far beyond the limits of eight channels and can accommodate 64 channels of audio on a single Cat5e cable.

Very low-latency and very high-signal reproduction are two critical factors in sound transmission for the AV industry, so all three technologies stream uncompressed 24-bit audio, typically at 44.1kHz or 48kHz. Exactly how much latency is introduced varies by chipset and whether the audio is going through the analog to digital conversion process. According to Barani Subbiah, CEO of NetworkSound, "8-10 milliseconds is acceptable but anything beyond is a gray area for pro audio." Of the three chipset manufacturers, NetworkSound claims the lowest latency, under one millisecond (80 microseconds) while CobraNet has variable latency from 1.5 to 5.33 milliseconds, with the latter being the default mode of operation at 48kHz.

Of the three companies, only Digigram, makers of EtherSound, sells products directly to AV dealers or end users; the other companies provide chipsets to traditional AV gear manufacturers, including Biamp, MediaMatrix, and Gibson Guitars (MaGIC is the basis for Gibson’s new Les Paul guitars).

Interoperability continues to be an issue, as each of the three chipsets is only compatible with devices using the same chipset. While interoperability eventually will be addressed by current manufacturers or market dynamics, a brief window of opportunity exists for other product manufacturers, using standards-based codecs, to market products to address the AV industry vertical.