Electromagnetic Microphone

[timdevine]

Hey all,

I want to record the electromagnetic field produced by headphones from a distance of say, 5 to 20 cm. I figure something like a guitar pickup would work?

Are there any such microphones?

Any thoughts are most welcome!

Thanks in advance

Tim

 

[Resqueline]

Yes, a guitar pickup, or those old telephone pickup/recorder things with a suction cup. Interference problems increase with the cube of the distance though.

 

[timdevine]

Ah yes the telephone suction cups!

What about using an audio induction loop receiver? Like those in hearing aids.

Is it the same kind of field?

 

[duke37]

Hearing aids in UK have a T position to pick up signal from a telephone or audio loop. The signal is just the audio signal and the pick-up is just a coil, not a microphone. Most hearing aids have now gone digital and you may be able to find an old analogue hearing aid which would have both pick-up coil and matching amplifier. 5 to 20cm may be a problem since much modern equipment causes interference, particularly fluorescent lights.