How to disable the internal speaker in Lucid

[Frans Ketelaars]

On Tue, 01 Jun 2010 11:03:09 +0300, Amichai Rotman wrote:

Hi,

I recently installed Ubuntu Lucid after using Kubuntu Hardy LTS for a long
while (KDE 3.5.10).

I am trying to disable sound output to my internal speaker.

I have an HP DX2300 Mini Tower machine which has a full speaker on board.
There isn't a way to disable it in the BIOS without disabling the entire
on-board audio device, which I use.

In Hardy I found a way to tick all output devices in Kmix and then dable
the internal speaker.

I can't find the same in the Gnome Sound Preferences. When I turn off the
external speakers connected to the line out (green) plug of the on-board
card, the internal speaker continues to output sound, actually it does all
the time, but the external speakers mask it while on....

This is really annoying. I am no stranger to the CLI, but I am not sure
which .conf to change and where to look - I don't know PulseAudio that
well. I tried to use alsamixer under CLI, but when I turned off all volume
to PCM, the master volume was also affected....

Help!

Thanks!

Check this bug:
https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/485705

Also check if "headphone jack sense" is enabled:
https://bugs.launchpad.net/ubuntu/+source/hal/+bug/126150

Good luck!

    -Frans