i have a wireless speaker (discovery channel expedition wireless speakers) with a usb port to plug into my computer but i am not getting any sound from them. Do i need to buy a soundcard that specifically has a usb port or do i have something set wrong on my computer that will let my sound signal go out through the usb . Is there an adapter that would let me use the usb port with my reg round audio outputs. Pretty confused. Thx for your help.