[alsa-devel] [Intel HDA][ALC3226] Too much white noise from microphone

[Alexander E. Patrakov]

05.02.2015 02:13, Shawn Starr wrote:
> Hello ALSA devs,
>
> I spoke to patrakov on Freenode from the #Alsa IRC channel and they mentioned that
> the noise background I am experiencing is not normal. I tried two different headsets,
> both headsets have two separate jacks, the same result.
>
> I will test any patches/quirks for kernel as needed.
>
> Here is the alsa-info:
>
> http://www.alsa-project.org/db/?f=29d3c45e2d66c58be03a10bd0186067a9d735a11

I am not an expert on Intel HDA cards, but... some microphones are picky 
about the reference voltage supplied by the soundcard. You can change 
this temporarily, for debugging purposes, with hda-analyzer. See general 
instructions at

http://www.alsa-project.org/main/index.php/HDA_Analyzer

Note: it needs the "snd-hwdep" module loaded, and needs to be run as root.

In your case, you need to select Node[0x18] PIN in the left pane, and, 
at the bottom of the right pane, select 50 or 100 instead of 80 in the 
VREF box. See https://imgur.com/F84raSN for a screenshot based on your 
alsa-info.

If this doesn't help, just click around randomly. Maybe you'll find the 
magic checkbox that makes the noise go away and the voice stay :) - if 
that happens, please email the resulting diff file that hda-analyzer 
creates.

-- 
Alexander E. Patrakov