I just bought a Mackie 400F and an ART digital MPA.I have eveything hooked up the way i need and the 400f is wonderful.The one thing I can't seem to figure out is how to use the ART in Ableton Live 6.
I produce drum n bass and want to run my audio samples thru the ART to beef em up.What is the best way to do that.Here some pics to give ya an idea.

Mackie 400F:
http://www.dolphinmusic.co.uk/shop_image/product/bdccef...7b32d68923e24d36.jpg

Art digital MPA:
http://www.soundonsound.com/sos/jul04/images/artdigital2.l.jpg

Well, I've never used live before, but most DAWs will let you route an aux send out for headphone mixes and such. So do whatever is needed to do that in live and then set the out put for onyx outputs 3/4. Now patch the outputs to the inputs of your MPA(you may or may not need a reamping device) and assign the spdif inputs to a new track and record it. Now some DAWs have easier ways of patching outboard gear so check, but this way will work. Just make sure the new track(s) you're bouncing to aren't send to the same aux send as to avoid a feed back loop. Hope this helps.

Lance