Ambient noise cancelation for microphone circuit Will this work?????

[dllegere]

Hi all new to this site and I need some help. I am trying to make a microphone to listen to a wristwatch and want to cancel the ambient noise in the room. I have included a circuit that I plagiarized from a headphone cancelation circuit. Will this circuit that I have drawn here work. Whoops forgot to include the Schematic I will have it up in a minuite**broken link removed**

 

[MikeMl]

Why not just do what aircraft noise-canceling microphones do; just wire two dynamic microphone elements back to pack with opposite polarities? Colocate the two elements, but mount them with one facing the desired sound source, and the other one facing away. Both pick up ambient noise from a distant source, but the local coupling to the near element provides the selectivity. This way your amplifier line-up is much simpler.

 

[dllegere]

Thanks Mike what do you mean by local coupling?

 

[MikeMl]

Thanks Mike what do you mean by local coupling?

Aircraft noise-canceling mics are very effective in eliminating the ambient noise in the cockpit, but they must be correctly located with respect to the speaker's mouth. You have to adjust them so that they are ~1/4" from your lips, and so that you talk into one mic, while the other is on the opposite side, facing the other way. If you screw up and rotate the mic boom so that both mics are equidistant to the speaker's lips, then you cancel the voice, as well as the ambient noise. That is what I meant by "local coupling".

 

[dllegere]

OK got it, should be no problem I will make mics movable until it work right and I have the trim pot too. Thnaks Mike!!

If anyone could prototype this that would be great I don't have the parts yet to do it (on order).