From mboxrd@z Thu Jan  1 00:00:00 1970
From: Takashi Iwai <tiwai@suse.de>
Subject: Re: A tweak to the intel codec to get rid of the hiss.
Date: Mon, 11 Apr 2016 15:51:20 +0200
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To: Cyrille Dunant <cfd30@cam.ac.uk>
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On Fri, 08 Apr 2016 14:02:37 +0200,
Cyrille Dunant wrote:
> 
> I apologise for the noise on the list, but I noted that on a number of HDA 
> card, the default produces a small static noise, and I tracked it down to some 
> channels which I believe ought to be muted.
> 
> Attached is the output of alsa-info.sh, and the diff from the python hda tweak 
> tool.
> 
> This helped both for my laptop and desktop (both HDA cards, different models).

The recent kernel already provides "Loopback Mixing" enum control, and
this should reduce the noise on codecs like yours.  Give it a try.


Takashi