I am currently using an 8 channel Mackie Onyx Blackbird connected to a Windows XP Pro PC via Firewire, and the Blackbird also connects to a Mackie 24 Channel analog mixer via it’s channel inserts. The mixer connects to the PC via an “AUX Send” and plugs into the PC’s sound card “Line In” jack. The Blackbird came with Mackie Tracktion DAW software, which I loaded on the PC. I don’t like the Tracktion DAW because you can’t see the waveform being recorded “real time”. It only becomes visible after you stop the recording. I know you can watch the waveform in Audacity (2.0.3), but I’ve never used it with a multi channel digital recording device. I’ve only used it to record one channel off of the PC, that was fed a signal from the mixer. Will Audacity work as a basic capability replacement (my needs are simple) for Tracktion? If so, how should the connections be made? What settings will I use in the Audacity setup? The Audacity manual doesn’t cover much more than simple connections, with very basic equipment. I’m only a recording novice, with more than single channel recording needs, supporting my church.
If the Onyx is connected to the computer via FireWire, what’s the analog connection for?
Audacity will not play back multi-channel (over 2), but it will record, I think, up to 64. The problem is Audacity will only manage one Device at a time, so the trick is to prevent your sound system from breaking up the channels into stereo devices, a very common problem.
“We can record one and two, or three and four, or five and six.”
Koz
I’d say if you are multi-tracking, you should just get used to Tracktion… I assume there are recording level meters? You know… For about 50 years people recorded with analog tape, and they never saw a waveform! 
(The waveform is really nice for editing.)
If you really hate Tracktion, there other DAWs out there, but they all have their quirks and they all have a pretty big learning curve. REAPER might be worth checking-out, but I don’t know if it shows the waveform while recording. It’s affordable ($60 USD for home & small business use) and that’s for the full-version. There is no “pro version”, but there is a more expensive pro license if you make “big bucks” from using it.