Hello everyone.
I just purchased this: http://www.quasarelectronics.com/cpm003.htm -
It is an electret mic/preamp combo. I have 2 questions about interfacing it.
Firstly, the documentation states that it wants "mains filtered 12v DC, fused" to operate.
If I plug the Arduino into the mains using a 12v adapter, then use the Vin pin of the Arduino to the + of the modules power input, and then the - of the modules power input to Arduino ground, will that do the trick?
Secondly, I will be hooking up the output of this unit to speakers, which is straightforward; however, I would also like to use the output level to use as a sensor to an Arduino ADC pin.
WHat might I have to do to convert this to a usable signal to plug into an Arduino pin?
Best, Jeremy
Secondly, I will be hooking up the output of this unit to speakers, which is straightforward...
Not so straight forward. The module is a microphone/preamp assembly, it's output impedeance is no where near strong enough ( 1,000 ohms) to drive a speaker (most are 4-8 ohms) without additional amplification.
Lefty
Thank you both for getting back to me.
Lefty - I will be using an amp/speaker combination on the other end, so that should be covered. Forgot to mention that bit. 
Richard - This is exactly what I meant, I want to send the audio signal to the amp/speakers, while simultaneously sampling its amplitude level with the Arduino.
Any advice or tips on the rectifier filter set up would be appreciated - think I get rectification (converts an ac signal into a DC signal), but the specifics of how to do it (in addition to the filtering) are hazy to me in the practical realm.
As far as further power conditioning goes, I will cross that bridge when I come to it - for now I was more worried about proper safety as it will be mains powered!
Thanks again, Jeremy
Thank you Richard.
The audio signal will be sent to a speaker which will be in a feedback loop with the microphone - the point of detecting the volume of the audio signal is so the speaker is turned down when it starts to feed back.
I am thinking that the peak detector circuit may be the best best for this, yes?
Also, I found this: http://itp.nyu.edu/physcomp/sensors/Reports/CondenserMicrophones
Might the rectifier/lowpass part of this circuit (minus the amplification bits) work in conjunction with the pre built bit of the circuit, or is this circuit too basic to do all the DC scaling and the like?
Thanks again Richard, I'm glad I asked!
This is making more sense to me now I think. The NYU page circuite would then amount to a have wave rectifier, with the filter providing the averaging...
If that's correct I think I have enough to go on..
Excellent. Thank you again for all your help!
Best, Jeremy