Audio interface and mixer for camcorder

[flyboy627]

Hey yal, I'm looking for a solution to pipe aircraft comunications audio along with ambiant audio into my camcorder external mic input. Direct input from the airplane's comm audio has way too much gain for the camcorder to handle. I need to come up with a device that will mix the amplified comm audio ouput (radio comunications) and a microphone for ambiant cabin noise (engines and propellers). Any ideas?

Thanks, Flyboy

[Externet]

Hi.
Trying to come up with a simple thing avoiding an active mixer circuit, I would try a tiny center tapped -dime size- audio transformer out of a defunct transistor radio.

-Connect the (-) of a small speaker that will work as microphone (or a low impedance dynamic microphone capsule) and the ground from your comm audio source together to the center tap CT of the transformer.

-Connect the speaker (+) (or dynamic mic.)terminal to one end of the same winding UUUU.

-Connect the amplified comm audio source '+' to the other end of the transformer winding UUUU, with a 100K potentiometer in series.

-Connect the higher impedance 'secondary' of the transformer to the microphone input of the recorder.

-Calibrate the desired mix balance with the potentiometer.

Come back with results...

Comm+----100k----UUUUUU---CT---UUUUU----SPK+

Miguel

[MicroRem]

I can tell you how I did it years ago while shooting some video (Betamax even) in the back of a USCG HH3-F helicopter. I simply put a small mic into my headset and plugged it into the the camcorder. That way I got all the audio from the radios and IC. Capturing some of the ambient noise was not a problem in a beast like a Jolly Green, but may be an issue if you have a quieter aircraft.

Have fun

Tom

[philba]

take a look at the discover audio mixer section http://www.discovercircuits.com/A/au-mixer.htm

there should be something in there for you.