Started recording sermons at church through garageband on my 2013 rMBP. I am going out of the Yamaha 24 Channel Mixer into a iMic USB audio adapter. Between the board and the Mac there is a ground loop isolator. Last night when recording, there was static. Couldn't figure out why. Any help you could offer I would appreciate it greatly. Thanks.
MacBook Pro with Retina display, OS X Mountain Lion (10.8.3)