9 September 2008 - 22:04recording from two USB devices at once (on a mac)

Say you’re using one of the Macbooks in the soundlab and for some strange reason you need to record simultaneously from two separate USB devices. For this example I’ll use one of the Roland UA-25s and the Glottal Systems E.G.G. because the E.G.G. seems to have a really terrible preamp (loads of hiss even with gain on “low” and even using the Behringer ECM8000 Mic designed for it) and I like to use the Roland to record audio while using the E.G.G. to record the glottal pulses.

1. plug-in both devices
2. launch Applications/Utilities/Audio Midi Setup.app (I know the name makes it seems like this is for Midi only, but it’s really “Audio and Midi Setup”, go figure.)
3. Select Audio –> “Open Aggregate Device Editor”
4. Click the [ + ] button.
5. Click on the new Aggregate Device name and rename it something useful and informative like “Roland UA-25 and E.G.G. Stereo”.
6. Check the “Use” checkbox next to the Edirol (Roland) UA-25 and the E.G.G. devices in the “Structure” box.
7. (optional) Drag the devices around if you know you want one on the right channel and one on the left.
8. Click “Done” and quit the poorly named Audio MIDI Setup.

Now you can open Praat or Audacity (or whatever) and record stereo “audio” with the nice, clean mono vox on one channel and the E.G.G. signal on another. Yay.

P.S. I wasn’t able to figure out how to do this on Windows. Probably it’s not possible. :)