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I have a Dell Inspiron 13 7348 laptop and in Ubuntu the speakers emit a constant hissing sound with an occasional click. The sound starts at the lightdm login screen. There is no hiss in Windows so this seems a specific problem to Ubuntu. Anyone have any ideas how to stop this? From reading around I've read a few suggestions to lower mic boost in alsamixer but i've tried this and its made no difference.

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I think I may have found a solution so I'm answering my own question! It might help someone else if they're struggling anyway. So heres what I did. I ran lsmod in a Terminal and saw that there were 3 different codecs in use:

  • snd_hda_codec_generic
  • snd_hda_codec_hdmi
  • snd_hda_codec_realtek

I have no idea if this is normal but I thought maybe they have something to do with it so I blacklisted them all in /etc/modprobe.d/blacklist.conf (by adding blacklist snd_hda_codec_xxxx at the end of the file). I also blacklisted snd_hda_intel just in case that was the culprit.

I then rebooted and the hissing sound was gone but so was all sound (guessing this is because of blacklisting snd_hda_intel).

So next step was to start unblacklisting the various things 1 by 1. First I unblacklisted snd_hda_intel and the hissing was still gone but the sound was back to normal!

Interestingly, even with the other 3 codecs blacklisted snd_hda_codec_generic and snd_hda_codec_hdmi still show up in lsmod. Is this because they're codecs and modules?

Anyway there is no snd_hda_codec_realtek showing so im guessing this might have been the cause of the hissing. So far I have not faced any other sound related problems so I'm not sure why snd_hda_codec_realtek was loaded but its all working so I'll leave it this way unless someone offers a better solution

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Try alsamixer from command line. Press F4 (capture)
Use left or right arrow key to highlight "Mic Boost". Use up/down arrow keys to adjust sound so that hiss is inaudible.

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  • Hi thanks for the suggestion, but as I mentioned in the question I have already tried this to no avail. It does not seem to be mic related as even muting mic input doesnt resolve the problem
    – user18181
    May 27, 2015 at 16:50

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