Ubuntu – make audio with only one stereo channel play through both speakers

I found the solution at ubuntuforums.org, here's the link:

http://ubuntuforums.org/showthread.php?t=1384860&p=8689164

Basically you switch from pulseaudio to alsa, and you enable something called crosstalk, that allows you to hear both channels without 'super imposing' them.

From alsa-info your sound card codec is IDT 92HD81B1X5 .

The codec model can also be found running this command:

lspci -v | grep -A7 -i "audio"

From this page HDA audio models.txt, the closest known codec is STAC92HD83 (IDT/sigmatel).

From this list, you see which option you can try (more or less randomly) in the /etc/modprobe.d/alsa-base.conf file until your speakers are ok:

STAC92HD83*
ref Reference board
hp-dv7-4000 HP dv-7 4000
hp_cNB11_intquad HP CNB models with 4 speakers
hp-zephyr HP Zephyr
hp-led HP with broken BIOS for mute LED
hp-inv-led HP with broken BIOS for inverted mute LED hp-mic-led HP with mic-mute LED
headset-jack Dell Latitude with a 4-pin headset jack
hp-envy-bass Pin fixup for HP Envy bass speaker (NID 0x0f)
hp-envy-ts-bass Pin fixup for HP Envy TS bass speaker (NID 0x10)
hp-bnb13-eq Hardware equalizer setup for HP laptops
auto BIOS setup (default)

To apply your first choice (f.i. the first in the list: "ref"), edit the alsabase.conf running this command:

sudo gedit /etc/modprobe.d/alsa-base.conf

Add this line at the end:
options snd-hda-intel model=ref
save , reboot and test speaker.
If not ok, try the next model (f.i. hp-dv7-4000) modifying again last line in alsa-base.conf to :
options snd-hda-intel model=hp-dv7-4000
Again, save , reboot and test speaker.
If you are lucky you will have 2 speakers ...

• If it stills not good after trying many models, install alsa-tools to run hdajackretask, which is a low level wiring program for HDA sound card:
  you can change codec output to physical jack connections : f.i. click "override" near "internal speaker" , then you can choose another output in the list (like line out ) to replace the present "speaker" which is not good. You will have to close every sound program, including alsamixer, and to unmute master fader (with alsamixer) when you have applied a change.
  Some info here