When I first got the laptop the speakers were working, but the first thing I did was to do a fresh install of Ubuntu (version 12.04 at the time). It took me a few weeks to notice, but the fresh install had left me with a laptop with no sound.
Periodically I tried to fix the problem always without any success. The final straw came when I had a long morning in Hannover, with only a little work to do before the meeting was to start in the afternoon. It was too cold to spend too long outside so I set about finding a fix.
Three hours and a lot of swearing and rebooting and I finally had sound working. Annoyingly I didn't write down exactly what I did to fix the problem, and so when last week I upgraded Ubuntu to the newest version (13.04) I found that I had no sound and couldn't remember how to fix the problem. It's taken me almost two hours to find the solution again so this time I'm writing this post to both help anyone else having the same problem and to stop me having to figure it all out for a third time next time I upgrade Ubuntu.
alsamixercontrol panel; you can see this in the screenshot. This looked promising but there was one problem -- When I ran
alsamixerI didn't have a Auto-Mute Mode option.
Another forty-five minutes of fruitless web searching followed before I eventually discovered a way of changing the audio driver to show all the available options. Unfortunately this uses the daily build of alsa which I expect is why it got disabled after the upgrade to the newest version of Ubuntu. Anyway, the trick is to run the following commands to add the relevant repository and then to install the daily build of alsa.
sudo apt-add-repository ppa:ubuntu-audio-dev/alsa-daily sudo apt-get update sudo apt-get install oem-audio-hda-daily-dkmsOnce completed you can then run
alsamixerand you should find that the Auto-Mute Mode has now helpfully appeared. Simply disable this option and you should find that you're sound starts working. As far as I understand this option is related to sensing if you have plugged headphones in and if the internal speakers should be disabled or not. This means, although I haven't tested this, that if you disable the Auto-Mute then plugging headphones in my not stop sound coming out of the speakers, but that is an easy problem to deal with.