Multi-channel sound input (WAS: Multi-channel sound output)

[Yuriy Tsibizov]

> For example,
> once I get the output working, a next question will be how to read
> from a microphone-quad (or more) while still getting phasing/etc.
> right.
As I know, there are no multichannel recording hardware with FreeBSD drivers available. It can be possible to use multichannel audio over FireWire  (like http://mackie.com/products/onyx1220/index.html mixer with FireWire option card) if you need exact phasing, but I'm not shure they use "Audio and Music Data Transmission Protocol 2.1" Audio-Over-Firewire (http://www.1394ta.org/Technology/Specifications/specifications.htm) that will be possible to implement or some proprietary protocol (and you will need to get technical info from Mackie). It will be possible that you will need to write non-audio driver to send raw FireWire data and process it later, to avoid small delays when you demultiplex several channels into separate PCM streams that can cause phase shifts.

Yuriy.