There is a very interesting discussion on
linux-audio-user@lists.linuxaudio.org about the feasibility of an open-source soundcard, communicating over ethernet.
This all started from someone complaining about the difficulty of getting decent drivers for either firewire or USB-2 cards and grew from there.
The major advantage of going over ethernet is that there is
no hardware needed at the computer end. You would have great difficulty these days finding a computer that didn't have at least 10/100base-T and early 'sweet-paper' calculations suggest this would be enough for 20 independent audio channels. Yes I did say 20
Something else very attractive is that a half-decent ethernet adaptor is connected via high frequency transformers, giving total isolation both for safety and eliminating ground loops.
As ethernet is a unversal standard, drivers for the proposed soundcard could easily be written for any current platform, and for any immediately forseeable one.
Currently I think we are on the verge of a couple of guys with connection to small hardware companies developing test rigs with off-the-shelf modules. This move is to find out the practial limits of the idea, and likely problems/constraints.
If the pilot looks good, then the next stage would be to have multiple cards on the network all synced to one master - whichever can produce the most stable timecode. This would almost certainly
not be the computer. Apart from anything else, in this scenario the computer doesn't need to have a soundcard at all.
The last idea, casually mooted would be a small single channel add-on module able to pick up radio mics (although there may be patent restrictions preventing that).
The whole development, hardware and software, is intended to be entirely open-source, so no vendor lock-in and no restriction on development and improvement.
This is all very exciting stuff