The Stealth Mic

By Bill Byrne

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A binaural recording system re-creates the way a person actually hears by placing 2 microphones at a distance of about 7" (roughly the distance between your ears), usually mounted on a dummy head or worn on the human recorder’s head. When played back on headphones, the binaural stereoeffect is preserved and is often quite remarkable in its realism. With some easy modifications, a pair of headphones can be turned into a binaural microphone with readily available materials and cheap parts. Better yet, I’ll show you how to make your own binaural mic, disguised as earbuds. In today’s iPod-saturated urban environment, no one ever notices someone wearing headphones. This makes earbuds an ideal prop for covering a hidden mic that’s plugged into a recording device, for various stealthy endeavors.

December 18, 2012, 9:48 pm PST

Steps

Step #1: Wire the binaural mic elements.

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Cut two 3' lengths of wrap wire in each of 2 colors. Solder these to the first microphone element’s 2 contacts.
Slide a couple inches of heat-shrink tubing over each connection, and heat it with a lighter. This will secure the connections. We want them to be as stationary as possible, as movement of these wires will create noise on the line.
Twist the 2 wires together, but not too tightly. Slip on another piece of heat-shrink, this time over both wires. Slide it up to about 2" from the mic element, then shrink it.
Repeat the same process with the second mic element. About 10" from the mic elements, slip another piece of heat-shrink tube over to combine all 4 wires. Keep track of which pair goes to which mic.