[alsa-devel] HDA Conexant: is mic boost possible?
Pablo N. Hess
phess at linuxnewmedia.com.br
Tue Sep 4 16:14:58 CEST 2007
I have to make the sound chip of a Itautec W7635 (= FIC VA250D) work on
a Gentoo(-based) distro (I'm now trying Sabayon).
It is a HDA-intel (Conexant codec).
Using my earphones as a stereo mic, recording with 'arecord -f cd' has
always worked perfectly fine, from alsa-driver-1.0.14 on.
However, when using a regular mono mic (like the ones that come in
common headsets), recording simply does *not* work.
Here's the quick info:
stereo mic: ok
mono mic: no input at all (very high volume already tried)
playback: ok (even better than with alsa-driver-1.0.14)
stereo mic: ok (seems better thatn with alsa-driver-1.0.14)
mono mic: *very* very low volume, bad quality, lots of low-volume
Now the paragraphed info:
Playback is perfectly ok since alsa-driver-1.0.14, just like recording
with an earphone as a stereo mic.
With alsa-driver-1.0.14, definitely no mono-mic input works, no matter
the settings at alsamixer.
With alsa-driver-1.0.15rc1, mono-mic input works very very bad
(extremely low volume, terrible quality, lots of clicks and noise).
I guess that the mono mic needs a mic boost in alsa-driver-1.0.15rc1.
However, with a 'grep -i "mic boost" .../pci/hda/*.c'
(alsa-driver-1.0.15rc1 source code), it seems that only patch-realtek.c
and patch-analog.c support this feature.
Is it even possible to add a mic boost feature to this codec?
The output of alsa-info.sh with alsa-driver-1.0.15rc1 is at:
Thanks a lot for any info, and congratulations to all of you for your
terrific work with ALSA.
More information about the Alsa-devel