6 Nov
2005
6 Nov
'05
12:27 p.m.
Hi!
I had a similar problem in my laptop when using a USB soundcard
(Edirol UA-25). For me it was not necessarily associated with xruns.
Since ardour doesn't record the noise, I would say that the problem is
not in jack, but in the alsa driver.
It sounded also more like a distortion than noise, since when the
output levels were low the effect was less noticeable.
I found empirically that harddisk writing operations like saving a
file in an application would sometimes make the distortion stop, I'll
be damned if I know why (interrupts?).
Anyway, setting my USB unit to work at 48 kHz made this problem
practically disappear.
HTH,
Luis
it happens randomly, while I play a soft synth, that
jack XRUNs once,
and the audio become crappy, noisy, like a kinda of digital
effect....bit crusher?
then all synthesizers (all audio apps) sound the same sh*t...
i tried recording with ardour the output, and the output is clean, so I
guess is a problem of sync or something that has to do with the hardware
(soundcard).
in order to record this noise, i had to connect the soundcard output in
its input and record it via analog in:
http://xaero.ath.cx/jackbug_stereo.wav.bz2 (it is a stereo file, with
the clean track panned on the left, and the dirty one on the right).
i hope it could be useful to debug the problem...
what other information I can provide useful for debug?
note that this happens with many version of alsa (1.0.9b, 1.0.10rc2,
1.0.7 or less) and with many kernels (gentoo-sources (slightly patched
for speed improvement), ck-sources, ck-sources+realtime-lsm)
i hope to solve this problem, since my audio desktop is unusable as si,
since audio crasher after playng for just 5 minutes :(