[LAU] lowest usable latency from a USB 1 device?

[S. Massy]

On Fri, Sep 16, 2011 at 02:11:35PM -0400, Paul Davis wrote:
> On Fri, Sep 16, 2011 at 2:02 PM, S. Massy <lists at wolfdream.ca> wrote:
> > On Fri, Sep 16, 2011 at 01:33:42PM -0400, Paul Davis wrote:
> >> if you can run a USB 1 class compliant audio device on your linux
> >> system with lower latency than the current minimum so far posted to
> >> this thread, please post with the settings you use and the type of
> >> device. if your best performance has already been posted, no need to
> >> repeat it.
> >>
> >> i'll get the ball rolling with 2048 frames. note that we are assuming
> >> 2 channels only, but duplex mode (simultaneous capture+playback).
> > Pardon my obtuseness, but... Well, are we talking frames per period, as
> > in the -p option in jack's audio driver?
> 
> in JACK terms, the combination of:
> 
>    * sample rate
>    * period size (frames per period)
>    * number of periods (periods per buffer)
With my Roland UA25EX I can run JACK with -r48000 -p64 -n3 without any
xruns or stability issue. Anything lower gets dicey. 

Cheers,
S.M.