I have a feeling I'm a pioneer on this topic since I can find very little on the 'net about this. Hence this thread: I am putting together a podcast where there will be two of us speaking, so I need two mics to be live at the same time. I like the idea of a condenser mic and the Samson C01U USB mic has been getting good reviews, so I decided to go that route. I intend on using either GarageBand or WireTapPro to record the program. I already owned one Samson C01U and it works great. I bought a second Samson C01U and connected it to my iBook along with the first one. I went to Audio/MIDI setup and created an aggregated device with the two mics. Then I opened WireTapPro and used the aggregated device as input. Both mics worked. So far so good. Then I noticed the mic that was feeding the right channel started buzzing very badly. I went into the Aggregate Device Editor again and clicked the "Resample" button. The buzzing went away. I also noticed that the applet that you can download from Samson stopped working as soon as two mics were connected. I guess it gets confused when it finds more than one device connected. After some more testing, I realized that one channel recorded significantly louder than the other. And I could find nowhere to adjust the volume of each channel, even in the Aggregate Device Editor. I killed WireTapPro and tried this with GarageBand. GarageBand's "Preferences" panel would not open for me at all while there were two mics connected. I'd click it and nothing would happen. If I removed one of the mics and restarted GarageBand, "Preferences" came up fine. At this point, I stopped messing around with the iBook and plugged both mics into my XP machine and fired up Adobe Audition. After a couple minutes of playing around with it, both mics were recognized and it worked just fine. My preference is to get this working on my iBook, since it's a more portable form factor. I'll keep everyone posted on my progress, and if anyone has any comments or suggestions, you're welcome to share them here!