“Stereo” contact microphone

A two-channel “stereo” contact mic, based on a design by Boston-area sound artist Michael Rosenstein. Made by modifying a 1/8″ stereo plug => 2x 1/4″ plug cable.

I cut off the two larger jacks and soldered large piezo discs onto each lead, then sealed the connections with shrink tubing and plasti-dip. I used red dip for the piezo disc that connects to the ring of the tip-ring-sleeve (TRS) mini-plug, which would be the right channel in a stereo configuration. I put “stereo” in quotes for this mic because, while it’s a two-channel mic that works great with a mini-plug input on any audio recorder, the recordings don’t attempt to depict a sound field like we expect from a stereo microphone array.

This means you can arrange the two elements in any relation to each other and it’s never “wrong.” In the above image, I clipped the two elements to each end of a strip of heavy watercolor paper, then left it out in the gently falling Western Massachusetts snow plugged into my Sony PCM D-100 digital recorder. The paper was heavy enough that it never became waterlogged, and was stiff enough that the snow made a satisfying pop upon impact. The result was a “stereo” recording of a tiny paper landscape.

In the below photo I’ve attached them to a wire shirt hanger, an adaptation of “The Watson,” a technique invented by environmental recordist Chris Watson for a quick, cheap, and effect stereo mount. (I’m not sure Watson himself invented the name for it.)