I have had a problem on Skype telling me there is excessive background noise - and people I'm talking to unable to hear me properly. I tried the other solutions but got varying results. Looking at the noise graph in the VX-6000 audio and video settings process the bar stayed either yellow/red without me talking or the microphone volume turned itself so low as to be useless.
I have taken the screw out of the back of the unit, prised the case apart and lifted the microphone (small cylinder with two wires attached) out of its inset. I have then stripped 5-10 mm from the ends from a 50mm (2 inch) piece of wire from telephone cable (very thin), inserted one end through the horizontal slit in the rear case of the unit , underneath where the microphone sits. I bent the wire over so the bottom metal case of the microphone would sit on top of the bared wire. I then reseated the microphone (while looking at the graph in the set up of the VX-6000) - once I had reassembled the unit the microphone is permanently in the green section of the graph. I have put the volume up to maximum with no buzzing problems - tested it on Skype and by recording a clip using the life cam software.
I did this as a last resort - my webcam is 8 months old and I would not get a refund so I had nothing to lose. It looks ugly but it works for me.
This is the one that worked for me...cheers spud66 you're a legend!