How to repair very noisy speaker in HP Pav...

Everytime the computer is off mute its very noisy, it used to only buzz for about 20 or 30 seconds on boot up but over thispast month it has gotten to the stage that it buzzing constantly when the sound is on.

Someone had mentioned that it may be the speaker cable shorting out, so how do I fix this problem? can I open up the computer and find the speaker easily?

Help with thiswould be very much appreciated.

Cheers