Microphone.
 

When I try to record something with my microphone there is alot of distortion. When I'm using this particular mic and I lift up the back of the computer there is no distortion. I have the correct mic options because when I use a different mic everything works fine. This mic is part of a sennheiser headset, and I had the same problem with my previous sennheiser headset, the connector is the same design. This problem is rather random, sometimes a restart will stop it, any ideas what is causing it or how to fix it?

Edit: I am pretty sure it's vibrations causing the interference because when I hold the back of the case down it goes away aswell. Pushing this down has fixed the problem for now. Though it comes back when I let go of the case.