Using a USB headset for speech recognition (Dragon 10) was no problem before I upgraded to Snow Leopard this morning. Since then the USB playback is chopped - sounds just like an old DMA access conflict, hacked into pieces. This is a Mac PRO 8-core, 6GB RAM, Vista Enterprise (3GB, 4 CPUs). I tested same on Macbook PRO, same symptoms. Audio playback via USB headset into MAC and using default settings in Parallels 4.0.3846 is fine, but microphone volume is not sufficient. Either way unusable! Any ideas?