Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I think it depends if the manufacturer provides a driver

Snow Leopard defaults to the 32-bit kernel so the driver should work.

If you want to use the 64-bit kernel than you would need to get a new 64-bit driver.

If it is a native USB audio device like a speaker than it should be supported by the native 64-bit USB driver.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.