On 10/30/2016 03:09 PM, Sebastià V. Amengual wrote:
I could be wrong, but as I understand, as far as the distance between
the microphones is much smaller than
the wavelength, it is possible to obtain first-order microphones with
any kind of directional pattern. Thus,
at least for a limited frequency range they could create the four
cardioid signals or directly the B format
signals, just using linear combinations of the signals (delay and sum).
Again, for a limited frequency range...
I am not sure how they would manage to get an acceptable directivity at
all frequencies...
You can, but yes, the frequency range :)
Also, I think things get even funnier when you consider you don't have
three pairs of omnis, for a differential receiver along each spatial
axis, but rather a tetrahedron of omnis, and the joys of mapping that to
B-format.
I'm trying to model that, but it gets very confusing very quickly... You
could make six dipoles, one along each edge. Then in addition to the
frightful EQ gains needed to make a fig8 work over a reasonable
frequency range, you have additional gains to shoehorn those dipoles
into three linearly independent components. Still trying to figure out
if that kinda cancels out in the end, but right now my gut feeling is
such a beast would be even more sensitive to capsule mismatch than a
traditional cardioid array. Add the terrible, terrible frequency
response of MEMs with their cavity resonance and not at all
omni-directional behaviour, throw in the effects of the (rather larger)
circuit boards depicted in the article, and you end up with something
that is frightful on so many levels that it might as well be a
Hallowe'en joke.
I worked on comparing different methods in my master thesis analyzing
the performance using different spacing
between microphones, just in case anyone is interested on this
http://www.diva-portal.org/smash/get/diva2:752195/FULLTEXT01.pdf
Thanks! I was also re-reading an excellent article about dipole mics by
Mark Williamson that someone posted here a while ago, unfortunately it
seems to have fallen off the web...
--
Jörn Nettingsmeier
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Tel. +49 177 7937487
Meister für Veranstaltungstechnik (Bühne/Studio), Tonmeister VDT
http://stackingdwarves.net
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