DIY
CIRCUITS
THE STEALTH MIC
Disguise an inexpensive binaural microphone as ordinary earbuds. By Bill Byrne
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 stereo
effect is preserved and is often quite remarkable
in its realism.
Photograph by Sam Murphy
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.
MATERIALS
Microphone condenser elements ( 2)
RadioShack part #270-090
Solid-core wrap wire, 30 gauge in 2 colors
Soldering iron and solder
1" heat-shrink tubing
Lighter
1" stereo plug
Earbud cushions
1. Wire the binaural mic elements.
Normally I don’t use wrap wire because it’s so thin
it can be frustrating to deal with, but in this case,
for earbuds, we really need the wires to be thin and
lightweight.
Cut two 3' lengths of wrap wire in each of 2 colors.
Solder these to the first microphone element’s 2
contacts (Figure A, next page). Slide a couple inches
Make: 161
