Using Aggregate Device in Audacity

I have been trying to aggregate two USB Headsets for use in Audacity by using the “Audio Midi Setup” on my mac - I have tried 2 USB headsets that are the same, as well aggregate 2 different brands. Without changing any of the default settings I have aggregated the two devices by checking the two boxes, made sure any “mute” box is unchecked in the input/output, and they have the same sample rate. When I choose the aggregate devices in Audacity and also set my playback and recording devices in “Preferences” to aggregate, I can only get one microphone to function properly. I have been playing around with this for hours - looking at forums and exploring many different settings and combinations. Any idea why it seems to me that the 2 microphones won’t properly aggregate? Or if they are aggregated properly, why Audacity doesn’t acknowledge both mics?

Thank you! I have a MacBook Pro mid-2010, OS X 10.8.5 and Audacity 2

How many channels does your aggregate device have?
How many channels are you recording? (look in the device toolbar).

and they have the same sample rate.

And channels? Audacity may drop dead if it tries to connect to a mono device with a stereo setting.

Also headsets can be a little magic as compared with a straight microphone(s). Do they each work individually? That is, my system will allow me to select either microphone or the aggregate when they’re plugged in together. Can you get all three?


I believe that I only have 1 channel for the microphone and one channel selected in audacity. When I test out the aggregate, the only microphone that works at all, is the “clock source” headset. I’ve attached two photos showing my aggregate settings and my audacity settings. See anything off or any other suggestions? THANK YOU!
Screen Shot 2015-05-07 at 8.37.42 PM.png
Screen Shot 2015-05-07 at 8.38.56 PM.png

Your aggregate device has two inputs (1 + 1 = 2) , so what happens if you set Audacity to record in stereo?

Do both mics record separately, one connected at a time?