On 23/03/2013 17:11, gregz wrote:
Eiron wrote:
Those electret microphone capsules are quite good but omnidirectional.
Is there any way to modify them to give a different pattern?
Modify the case, or some suitable shaped enclosure?

There are some digital recorders available with what looks,
though I haven't looked too closely, like two electret capsules
at right angles. If they are omnidirectional, they wouldn't give
much stereo effect. Anyone know what they are?


Without modifying the capsule, you can put a plate in-between them.
Pressure zone principal. You can mount the capsule flush on the plate. You
can use two plates at 90 degrees or more. I did this many years ago. The
bigger the plate, the lower the frequency of directionality.

I was looking at a capsule. It might be possible to drill a small hole in
this one. Looks like there is a rubber like seal on the back. That's to
make a rear entry point, but an extension of the rear would be needed.

http://www.pitt.edu/~szekeres/mic/wm63.jpg

Now try to put it back together!

It's probably possible to block the holes in this
http://cpc.farnell.com/jsp/level5/mo...cpc/405947.xml
with blu-tack and make it omnidirectional.

And at 50p each I'll buy a few to experiment (play) with.

--
Eiron.