Shotgun mikes are directional assuming plane waves of uniform amplitude. My understanding is that they work by essentially having a leaky acoustic waveguide with a mic capsule at one end. They may be less directional in a converging soundfield, and could become dispersive so introducing frequency response errors.Gnobuddy said:
Anyway, as you say, if you are using a mirror you want to illuminate most of it so nothing more directional than a hypercardiod.
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Oh gosh no, not at all.
Far as I can tell, I think you've (collectively) zeroed right in on it.. No lingering misunderstandings on my side as far as I am concerned!
As ever, this is a great forum and I do sincerely appreciate the generous help and good will of the membership at large. Glad I decided to join up.
-Billy
Coming back to this late, that Knowles ultrasonic mic I measured had relatively normal frequency response down below 50 Hz.
The trouble I've had with the WM electrets has been signal to noise. I always end up with way more noise than is acceptable. Not at all apples to apples, but I grabbed one of those inexpensive 1" diaphram mics when they first came out and with the proper phantom supply, the response and signal to noise just floored me. I think it was an MXL.
The trouble I've had with the WM electrets has been signal to noise. I always end up with way more noise than is acceptable. Not at all apples to apples, but I grabbed one of those inexpensive 1" diaphram mics when they first came out and with the proper phantom supply, the response and signal to noise just floored me. I think it was an MXL.
If it was flat from 50 Hz to 100kHz, that's quite impressive! Only one audio octave missing at the bottom end, and response far beyond the highest audio frequencies.
So far, I myself haven't run across any MEMS mic with specifications that good. But I haven't tried to do a comprehensive hunt for them, either.
Yeah, most MOSFETs are pretty noisy devices. Not a great choice for millivolt signals!
I have two or three different MXL mics I use for home recording. I've read all sorts of criticisms of them online, but, like you, I've been pleasantly surprised by how good they are.
-Gnobuddy
If you are talking about the Panasonic WM-61's etc., they are not MOSFET's and the noise is diaphragm physics limited. The noise goes as the sqrt of the acoustic resistance (the area) so a 1" mic is potentially way quieter than those tiny little capsules.
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We're talking actual statistical "shot noise" of air molecules bouncing off the mic diaphragm? Cool, I didn't know that! 😀
(Though I should have, given the resemblance to Brownian Motion, something I encountered in physics class a long time ago.)
-Gnobuddy
Yes, it's always frustrating trying to talk people out of trying to cobble a different FET into one of these tiny capsules. It can not make a difference.
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