[alsa-devel] via82xx DC offset at -30dB

Peter Plessas plessas at mur.at
Mon Oct 29 01:44:34 CET 2007

Dear List,

having a Compaq Presario notebook in front of me, running Debian testing
and a 2.6.18-4-686 kernel, i have a strange DC offset when trying to
record audio via the mic/line input. As the audacity level meters
suggest, it resides at -30dBFS.
Audio comes through and gets recorded though, but the offset severely
limits the headroom of course.
The sensitivity of the line/mic input seems to be quite high, although i
have the mic boost setting turned off of course.
Setting the module option ac97_quirk=yes did not help either.
Can it be that a soundcard of this strange behavior is manufactured, or
is it an alsa/driver issue? I really don't want to install another M$
operating system to check if it works there, so any help is deeply

lspci lists the device as:
00:07.5 Multimedia audio controller: VIA Technologies, Inc. VT82C686
AC97 Audio Controller (rev 20)

regards, PP

PS: please CC: me, as i am not subscribed to alsa-devel (yet)

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