Subject: RE: [linux-audio-user] HD noise with SB Live card
From: Mark W. Knecht (mknecht_AT_controlnet.com)
Date: Fri Aug 30 2002 - 01:27:15 EEST
Josh,
I have more experience under Windows. There you need to be pretty careful
about which interrupt the sound card is given by the system. If it get a low
priority interrupt you get what we normally term as 'clicks and pops'. In my
experience (again under Windows) if you can get the audio card on IRQ 9 or
10, then you are typically in pretty good shape.
I have ZERO experience with this problem under Linux as I'm just getting
started here.
Cheers,
Mark
-----Original Message-----
From: linux-audio-user-admin_AT_music.columbia.edu
[mailto:linux-audio-user-admin_AT_music.columbia.edu]On Behalf Of Josh
Green
Sent: Monday, August 26, 2002 1:02 PM
To: linux-audio-user_AT_music.columbia.edu
Subject: [linux-audio-user] HD noise with SB Live card
The problem I'm having is most likely not Linux specific, but I only run
Linux so I can't test to see if it also occurs in other OSes.
The problem is that I'm getting quite a lot of noise (little bleeps and
static) in the digital sound output of my SB Live card. If I do a large
copy of a file or something to really give the hard disk a work out, any
PCM audio output becomes totally in-audible as it is overwhelmed by
noise.
I'm convinced that this noise is not being picked up from the sound card
via electro-magnetic interference. The reason I think this is because
this all started when I changed motherboards from one with a K6-2 to a
PIII. Also if I disable DMA on the hard disk (hdparm -d 0 /dev/hda) the
problem goes away completely. Of course not having DMA is a real drag
for real time audio work.
If anyone has some knowledge as to what could be causing this, I would
love to hear it. I'm not real familiar with how the SB Live transfers
audio internally. I'm curious if there is something broken with the DMA
controller on my motherboard or perhaps some sort of conflict. It almost
sounds like the audio buffer is getting directly trashed (noise isn't
mixed with PCM audio, it replaces it).
Right now I'm looking to just get another motherboard, but I would like
to avoid this if possible. Cheers.
Josh Green
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