The humble blue Ethernet wiring could be the solution to the cost and complexity of cables in the live music scene, thanks to researchers from the Digital Audio Networking project at National ICT Australia (NICTA).
In the traditional live sound system, point-to-point copper cables run between a mixing desk and individual sound sources. Typical set ups involve multiple sources, such as guitars, percussion and vocals, and hence require what could very easily become a mess of copper cables.
And there is also the issue of "noise" caused by the degradation of an analog audio signal in copper. As such, cables are usually grouped in heavily shielded audio snakes, which can cost around $100 per metre.
"Copper is bulky, cumbersome and fragile," said John Judge, NICTA's senior research engineer on the project. "It's all very last century."
NICTA's design sidesteps the need for multiple cables and shielding by transporting audio signals between sound sources and the mixing desk in digital form. Audio signals are passed through analog to digital converters at the source, which convert audio samples into byte form that may be sent as network packets through a standard CAT-5 cable.
At the mixing desk, digital signals are converted back to analog form via digital to analog converters. In the future, however, researchers expect the technology to allow sounds to be mixed on a computer, thus eliminating the need for a second conversion, and further reducing costs.
Audio to digital converters have been around for some time, Judge explained, citing the microphone input of a computer's sound card as an example. So, for NICTA engineers, it was all simply a matter of utilizing existing convertors and creating the technology to interface with standard computer networks.
Besides the interface boxes that were designed as converters, all other components of the system are off-the-shelf networking hardware. As each source may be treated as a node on the network, a single Ethernet cable is able to deliver multitracked, uncompressed data to the mixing desk.
The most challenging problem the engineers had to face was network latency: slight delays in converting audio streams from analog to digital and back could put the sounds out of synchronisation with the live performance. It took two years of research for a method of getting the delay below a two-millisecond threshold to be invented.
So how did researchers overcome the delay? "We were creative," Judge said, cryptically.
The technology will soon be commercialised by a spin-off company named Audinate. So far, Judge said, "a range of companies across the professional audio spectrum" have expressed interest in the technology.