Over the past week or two, the performance of my microphone on my 8220 headset has degraded. It seems like it is a mechanical/electrical issue. When I have the headset down by my mouth it creates buzzing when unmuted. If I movet he microphone slightly up or down eventually i can find a spot where the buzzing goes away. I suspect a noising connection inside the microphone. The issue goes away when muted. Can anyone help me understand or troubleshoot this issue?