Fig. A: The microphone element soldered to 30-gauge
wrap wire. Fig. B: Heat-shrink tubing reinforces connections to avoid introducing noise. Fig. C: Both elements
wired and reinforced. Fig. D: Wire each element to the
of heat-shrink tubing over each connection, and
heat it with a lighter. This will secure the connections (Figure B). 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 (Figure C).
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.
2. Wire the stereo plug.
Open the stereo plug, and slide the cover over the
4 wires. Here’s the trickiest part: in order to have
the correct stereo image, the wires on 1 of the 2
mic elements should be reversed. So, for one mic
element, the red goes to a plug terminal, and the
blue to the plug’s ground; on the other mic element,
the blue goes to the second plug terminal and the
red goes to the ground (Figure D).
Solder these connections, then screw the cover
back on the plug.
162 Make: Volume 17
stereo plug in opposite directions, with ground (in back)
connecting to blue on one, red on the other. Plug tip is
the right channel, and sleeve (middle) is left. Fig. E: The
finished microphone passes as earbuds.
3. Disguise the mics as earbuds.
Fasten the earbud cushions over the mic elements
so that they’re large enough to sit comfortably in
your ears (Figure E). That’s it, you’re done.
To hear exactly what’s being recorded, some folks will
actually use a mannequin’s head to hold the binaural
mic, and will hold the head in their hands while
wearing a pair of normal headphones to monitor the
sounds. Working this way creates the amazing effect
of listening to a binaural recording as it happens, but
keep in mind that if you walk around holding a dummy
head out in front of you, you may attract attention
(in fact, I think you’d get arrested in some places).
With these stealth binaural mic headphones, as
long as you’re in a situation in which it’s socially
acceptable to be wearing headphones, you can
record away, knowing that what you hear will be
very close to what you play back later.
Photography by Bill Byrne
For a schematic diagram and list of recordings,
go to makezine.com/17/diycircuits_mic.
Bill Byrne is a multimedia artist, motion graphics designer, and
educator. He wrote about Wii control in MAKE, Volume 14.