7 Mar
2005
7 Mar
'05
3:03 p.m.
On Mon, Mar 07, 2005 at 11:03:50AM -0600, Jack O'Quin wrote:
I have a Terratec Producer Phase 26 USB soundcard and I have intensively
tested 2.4 and 2.6 kernel for stability for hours and lower latency, the best
result is with the gentoo-sources 2.4.28 (gentoo kernel are already
patches for all audio needs)
I run jackd with
Frames/Period = 256
Sample Rate = 48000
Periods/Buffer = 3
wich provides a 16ms latency
If I try to go lower, I have xruns when I connect/disconnect clients.
Regards
Philippe
Is there an
inherent minimum latency for USB soundcards?
I have no USB sound card. Perhaps someone else can answer that
question.
There *are* reported latency problems with USB, ALSA and JACK due to
isochronous USB data transfers and JACK's need for a constant power of
two buffer size. IIUC, USB sends a block every 1ms. With some sample
rates this does not result in a constant number of samples in every
block. Progress has been made with certain specific devices (usx2y),
but I believe the general problem still remains.
These issues seem to become more intrusive at lower latencies. But, I
really don't know what the limits are for your device.