Small Dynamic Mic Elements

Drone · Post by **Drone** » Sun Aug 18, 2013 3:18 pm

Anyone have a source for small (about 1cm or .5") dynamic mic elements?

Currently I'm using an earbud element connected to the transformer from a 57, my problem is it's too sensitive and the cartridge distorts at moderate SPL. I need something a bit more robust, fidelity and frequency response take a back seat in this instance, as you may have deduced. Size and SPL handling are the main parameters.

ubertar · Post by **ubertar** » Mon Aug 19, 2013 7:19 am

Is this project top-secret, or can you tell us a bit about what you're doing? Sounds interesting.

Drone · Post by **Drone** » Fri Aug 23, 2013 12:41 pm

Nothing too exciting, I'm fitting the microphone into something, and that is the size of the aperture I've got to work with. I can't make it any larger without a large amount of hassle, and not just for me, and I can't use an electret because it has to be passive.

Scodiddly · Post by **Scodiddly** » Fri Aug 23, 2013 5:12 pm

You could try earbud-sized speakers - with dynamic stuff you can use a mic as a speaker and vice-versa.

Drone · Post by **Drone** » Sat Aug 31, 2013 5:27 pm

Err yes, that's what I'm currently using, the problem is it's too sensitive. I need something with a bit more SPL resistance. I suppose I could just spray some kind of gunk into the cavity in front of it, but that's really going to make it sound muffled isn't it?

ubertar · Post by **ubertar** » Sun Sep 01, 2013 7:15 am

Maybe this would work: http://www.goldmine-elec-products.com/p ... ber=G19512

Drone · Post by **Drone** » Sun Sep 01, 2013 6:48 pm

Cool, I'll maybe give it and this a try, make up that $10 minimum.

http://www.goldmine-elec-products.com/p ... ber=G15681

Scodiddly · Post by **Scodiddly** » Mon Sep 02, 2013 6:03 pm

Sorry, I missed the "earbud" word.

A small resistor in series might be worth a try. I can't imagine an acoustic source moving the diaphragm more than an headphone signal. So it's likely more an impedance issue.

themagicmanmdt · Post by **themagicmanmdt** » Mon Sep 02, 2013 9:17 pm

why hook the transformer up? are you using a long run and need it balanced?

themagicmanmdt · Post by **themagicmanmdt** » Mon Sep 02, 2013 9:17 pm

why hook the transformer up? are you using a long run and need it balanced?

Drone · Post by **Drone** » Sun Sep 08, 2013 11:01 am

Yes, at one point it was running into a box, and along the snake to a house mixer. I was trying to make it as much of a 'real' microphone as I could.

If you can picture a malleable funnel, with the mic glued in the narrow end, and someones face in the big end, that's kind of what I've got here, except with a bit more twists and turns, there are a couple of small places air can escape, but my worry is, it's the air pressure as well as the sound pressure that is overloading the ear bud, sound likely?

The Scum · Post by **The Scum** » Thu Sep 12, 2013 7:23 pm

I know it's not exactly passive, but MEMS mics are extremely tiny. Tiny enough that using them is questionable for the average DIYer.

Here's one in usable form:
https://www.sparkfun.com/products/9868

You may be into some resistor swapping to change the opamp gain...I seem to recall that it clips at about 90 dB SPL, but the mic is rated to 120.

Full disclosure: I'm an employee of Sparkfun.

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Small Dynamic Mic Elements

Small Dynamic Mic Elements

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