Joe Albano take sus through the ins and outs of creating aggregate audio devices for Mac users and explains why and in what situations you'd want to consider doing this.
If you have multiple audio interfaces, synthesizers, or even iPad interfaces, you can get them to all work as one virtual interface on the Mac. Here's how to combine them as an aggregate device.
Need more inputs or outputs than your current audio interface provides? Got 2 interfaces? Running Mac OS X? Hollin Jones explains how Audio MIDI Setup can fool your DAW into using two devices as one!