In article , Eiron
wrote:
On 22/03/2013 19:03, Dave Plowman (News) wrote:
In article , 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?

I'd say not. Producing a cardiod capsule requires precision
engineering. So cheaper to simply buy one.

You're right. They seem to be 50p each at Farnell. It looks like they
just have a few precision drilled holes in the back. I wonder if that's
the only difference.

In principle you can get two pressure-sensing mics and place them slightly
apart. Then connect so that their outputs 'cancel'. This produced a setup
that outputs the 'differential' in pressure along the direction between
them. So gives a cardiod-ish shape. But although neat in theory you may
find it hard to get such a system working well. And it would need frequency
(wavelength) correction. So as Dave says, there is a lot of detail to sort
out. Simpler to buy the tool for the job unless you are interested in the
DIY experimentation involved and have the time.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html