Digital Sound Desks (03 Mar 2003)

This is the current sound desk that Imperial Union use. As analog desks go it's really nice, but one cannot help but wonder, everytime that it's used, if a digital one wouldn't be better.

I can decode an ogg stream, FFT it, FFT it back and write it to the sound card using 30% of one of my PII 450s. That suggests that I could process about 6 CD quality streams in real time. That's not helpful as we have 32 incoming XLR feeds. Also, quality ADCs output 96Khz, 24-bit and I could only manage a couple of those.

Thankfully, FFT is pretty simple operation and a Xilinx (or 2, or 3 etc) could handle all 32 96/24 streams. A quick calculation suggest that it's 4.6 MB/s (remembering that a real domain FFT can throw away half the results) and that's easy to handle.

Still, I might see if I can simulate some 3D spaces with sound in them and have a play about with feedback suppression etc.