Was wondering if you good people could give me any suggestions or pointers regarding Aggregate Audio, and whether there's anyone out there with a similar setup to myself who's actually got it working for them, or indeed if there are alternatives that do work.

I'm using a MacPro running 10.6.3 with a PCI MOTU 2408 (two units running off the PCI Firewire) and have recently purchased an Apogee Ensemble. I have a Mackie 32:8:2 Mixing desk and was looking to run the 3 soundcards in parallel to give me 24 channels of audio on the desk, but the Mac isn't playing ball.

I have set up an aggregate audio device to include all units, but if I go into my DAW (for argument's sake Ableton Live as I use it the most), although the aggregate device is shown in the Audio Preferences Menu, whilst it says 24 channels, the MOTUs don't playback anything, just the Apogee. If I switch to just the PCI card, then the MOTUs work fine, and likewise with the Apogee.

Is there anything specific I'm doing wrong here, or is it the case as I fear from having read various board comments, that actually aggregate audio simply doesn't work other than in the simplest combinations (eg. Mac Audio & a firewire Soundcard)?

Hoping you can help,