> <<Well, it's actually about thirty feet deep at the bottom end...>>
>
> Sure, but that's just a fraction of the entire audible range. Dan,
> when you say there's no such thing as a pressure zone, I'm assuming
> you mean for all possible frequencies, right? However, if we limit our =
> concern to everything below, say, 16kHz or 18kHz, then certainly we
> can say a pressure zone devoid of audible comb filtering exists within =
> that band.
Sure, but I question the use of the concept "zone" when the more useful con=
cept is wavelength. Question: what is the depth of the "zone" that will not=
produce comb filtering below 16kHz?
> Further, I would suggest that a perfectly flat frequency
> response at the very top limit of our hearing, the half octave above
> maybe 12kHz is just not absolutely critical to a well defined overall =
> sense of a balanced spectrum.
Agreed.
> When PZM's first became available, late 1970's I recall it was, my
> studio partner & I got one . We recorded everything with it; piano,
> double bass, violin, acoustic guitar, vocals, woodwinds. Then after a =
> month or two of infatuation we went back to using our U87's & KM84's
> for all the things they excel at, & more or less put away the PZM for =
> good. I believe we suffered from the "New Girlfriend Syndrome".
> Critical examination of the results revealed that what is in fact a
> hearing aid capsule simply doesn't compete, resolution-wise, with the =
> 1/2" to 1" diaphragms in the various Neumanns & Sennheisers we had on =
> hand.
I was involved in a "purist" jazz session once (with engineer Paul Stubbleb=
ine, I think) where huge plexi panels rigged with boundary mics were hung o=
ver the players. That didn't last.
> The results that Paul obtained, showing significant cancellation in
> the high end, is indicative of the fact that placing a mic body on the =
> boundary with the capsule perpendicular to the boundary doesn't locate =
> the diaphragm sufficiently within the pressure zone for those
> frequencies. Obviously part of the diaphragm is in & part of the
> diaphragm is out of the zone.
Yes.
> The Schoeps boundary mic places the
> diaphragm flush with the boundary, & thus is truly reflection free at =
> all frequencies.
Yes. The SASS does that, too, with the advantage that the diaphragms also f=
ace forward. The SASS "nose" is padded to reduce reflection coloration, sam=
e as with the Jecklin disk.
-Dan
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