On Sat, Nov 22, 2003 at 02:27:44PM -0800, Wolfgang  S. Rupprecht wrote:
> 
> tls@rek.tjls.com (Thor Lancelot Simon) writes:
> > Read what he said more carefully: latency for the _controls_, which are
> > actually separate USB features from the audio device itself.  I use a
> > Griffin iMic as an audio output device to play MPEG and Windows Media
> > files all the time -- no problems to report as yet, and the iMic has
> > really great output quality.
> 
> Oh I read it carefully enough, thank you very much.  The fact that the
> controls had a lag were not lost on me.  What I had assumed, perhaps
> incorrectly, but then perhaps not, was that the audio buffering was so
> long that changes in the controls would take a while to trickle out to
> the speakers.

USB audio uses an "isochronous pipe", which is not the mode used by most
USB devices.  If you look at the data rates of the USB bus and the audio
in question, it's pretty clear that sync within the sensitivity of the
human ear should be maintainable for quite a few more than two streams at
once; and indeed, this coincides with my experience.

Thor