DIY super lapel mic

I’m doing a project which requires a lapel mic be used to record voice alongside video on my Pentax K7, while the camera is some distance away. The project’s budget doesn’t stretch to actually buying anything – let alone using a dedicated sound recorder – so I modified a cheap little electret condenser mic, which was $3 from DealExtreme – This one, infact :

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I bought the silly thing a few months earlier and knew from my tests that it worked OK, but sounded crappy just by virtue of being so close to the camera. Normally an electret mic would require a power supply, so either the camera is providing that or – more likely I think – the camera just cranks the gain up. This one has three pins and the sound on the video is stereo, so I’d say that its just splitting the signal over both channels, maybe using a 10K resistor or something.

The audio sounds OK when you speak closely, so I decided to just lengthen the thing by about 3 meters or so. Rather than cut the jack off, and have to find twin-core shielded audio cable, I decided to sever the thing right where the mic attaches. This would mean that its small enough to hide under a collar too.

I wasn’t sure that the voltage drop over the length of cable would be a problem, but it turned out not to be. What frightened me was how tiny those wires are! Seriously – so small.

Oh man! They’re freaking tiny! This is the mic side, a bit more manageable.

Tinning both ends with solder before joining them helps enormously. The solder join isn’t that great but good enough – I’ve found that if you try to ‘make this better’ like this, they always end up worse.