Not only play but digitally record through usb. I used the 7k as a brilliant music laptop digital sound system for years. It is also a high quality A/D converter for any mic or line in. The midi and audio usb can be used simultaneously and sequencer synced to audio playback from the sd card, and if you have a device with only midi terminals and a pc with only usb, the 7k can be used as an interface to enable communication between midi device and usb pc.