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

[david]

S. Massy wrote:
> 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. 

64 msec latency is best I can do with my UCA202, -r48000 -p1024 -n3, but 
not 2-way (that's playback only), on non-RT kernel. Recording doesn't 
work through JACK at the moment, error message says something about 
impossible sample size.

-- 
David
gnome at hawaii.rr.com
authenticity, honesty, community