Laptop speakers whistling when I connect the jack for earphones

Hi, I have Acer Extensa 5220. After installing Ubuntu, the laptop speakers began to produce a high pitched whistle noise when I connect the jack for earphones or external speakers. Maybe it has something to do muting the speakers when the jack is in - they are mute but they squeal all the time. This problem never occur ed with Windows so it seems to be a software issue.
Can anyone tell help me with this,
Thanks.

Laptop speakers whistling when I connect the jack for earphones

Please see: http://ubuntuforums.org/showthread.php?t=874660

Your laptop has an internal mic. Turn it off and the squealing should stop when you connect the headphones. You are probably getting feedback.

My apologies for the late

My apologies for the late response, but I'm experiencing a tremendous # of issues concerning laptop speakers and the Ubuntu operating system. I disabled the internal microphone and I'm still getting really bad feedback. I'm wanting to hook the laptop up to some home theater systems, but I'm fearful this glitch may affect it as well. At this point, I'm not sure if it's a hardware issue. Can someone perhaps upload what they're hearing? I'm curious to know if what you guys are hearing is similar to what I'm hearing. Thank you!!!

...

Turning the internal mike off does not help. This is a constant high pitched sound that comes from the laptop speakers even when I mute everything. Might have something to do with hard disc spinning. The sound card in this computer is nothing special but I still think it's caused by different sound drivers or something like that. As I said, it came when I installed Ubuntu.

bad sound...

Please look at the following: http://ubuntuforums.org/showthread.php?t=789578&highlight=poor+sound

Also, if you look at your sound preferences, (right click the speaker icon), make sure you don't have 'duplex' selected for your input.