Odd Audio Issue

I've moved my Macbook Pro upstairs to be my main Mac. I have Bose USB speakers connected and also an MAudio Keystation25 for input in GarageBand and Logic. When I play a song in iTunes, it comes out of the speakers beautifully. If I run Garageband, I get no audio and then I get no audio in iTunes or anything until I reboot. When I press keys on my keyboard in GarageBand, I can see the input signals but can't hear any audio. The Bose USB are set as the audio output device. I tried it in Logic too and got the same results. Both seem to kill audio system wide until reboot. What could the problem be?

Well, I had the USB speakers connected to a hub so I connected them directly to the Mac's USB port and it seems to have solved the problem. It's just a shame that I have to use up a USB port and not my hub.