I have had problems with one of my kma/k133 mics. It hyper sensitive to physical tapping, but picked up very little airborne sound. When I tapped the body, the sound was like a metallic ringing sound. I tried to troubleshoot by swapping bodies around to see if it was the capsule or the body. Doing this made the problem go away. Is this simply a bad connection? Should the mic be sent to Neumann for a checkup? I would love to know if it is the body or the capsule that is the problem as the problem went away before I could be sure.