Noise cancelling microphone?

[sobazz]

Just a thought. Is it possible to make a noise cancelling microphone? I was mostly thinking of cancelling the self noise of cheap electret elements.

How can this be done? By casting one mic element into some sort of resin, and adding the inverted signal, or?

 

[sobazz]

I realize that the effect of casting a mic element into e.g. epoxy resin in order to dampen vibrations/sound is not effective at lower frequencies.

How effective is it at what frequencies? I suppose the noise of electret mics are typically limited to a certain frequency band not including lower frequencies, thus making it possible to add a high pass filter in order to avoid interference with THE signal. Has anyone studied this topic?

 

[SY]

It won't work- the noise that you're talking about is really noise. It will be uncorrelated between the two elements.

 

[sobazz]

Ok, thanks. Then it can't be dsp'ed out either.

 

[SY]

Nope. I wish there were an easy way to turn a Panasonic mike into a B&K, but there probably isn't.

 

[Da5id4Vz]

Nope. I wish there were an easy way to turn a Panasonic mike into a B&K,

All it takes is a phone call and a check that will clear.

I’ve been intrigued by the Linkwitz articles about hot rodding the Panasonic capsules. I have to confess that I have however been spoiled by good Mics. Perhaps that’s an even better reason to try. I’ve been curious about how far the concept can be taken.

(B&K mics are now marketed as DPA)

 

[SY]

It's a worthwhile improvement, but if you've got sausage-fingers like me, plan on destroying about as many capsules as you successfully mod.

 

[Da5id4Vz]

Yah, well that likely the other reason I haven’t done it (yet). I figure I'd get about a 30% acceptable yield. (on a good caffeine free day)

BTW, the good Mr, Linkwitz's article here:
http://www.linkwitzlab.com/sys_test.htm

(Is anyone else reminded of "Der Ring des Nibelungen" when the see his first name? Reminds me how boring my name can be)