Description of problem:
I discovered a very strange bug where there a two sockets used for sound. For
instance, I have a couple of loudspeakers connected to the rear socket and they
work fine, the sound is perfect.
If I plug the headphones (for instance) into the front socket, the rear sound
gets off (as it has to), but the sound from the headphones is really bad. But if
I unplug it a little (as if only one channel is used) the sound is fine again
(even if not perfect).
When completely plugged-in, the sound is again quite good only if I unbalance a
little right and left, or better if one is off (using the master settings). 

It seems to be still a stereo sound (not sure, by the way), and well balanced

Version-Release number of selected component (if applicable):
alsa-lib-1.0.12-2.fc6
alsa-utils-1.0.12-3.fc6

How reproducible:
Always
I have two different PCs, with different sound cards, different loud speakers,
different headphones and the effect is the same.  

Steps to Reproduce:
1. Use fron and rear sockets at the same time
2. Balance and unbalance the master settings
3.
  
Actual results:
Bad sound from front socket

Expected results:


Additional info:
I am not sure, but this seems to occurs only recently (say 15-20 days). I update
the system every day.