the vrvrvrvrvr sound produced by the Headphone when i touched the wall and the wires(going to the right) ? Answered

I have my headphone on my head, then i happened to be touching the headphone's metal arch(at the top through which the wires reach the right speakers) and the wall of my room at the same time, so then i heard a vrvrvrvrvrvrvrvrvrvrvrvrvrvr sound . Could any one help me identify this phenomenon?