I'm curious about Sony's arrangement of the 90 degree, near-coincident
microphones in the PCM-D1 and PCM-D50 recorders.. The capsules are
about 1cm apart -- but in the wrong direction. Because the left-
facing capsule is to the right of the right-facing capsule, the phase
differences created by the spacing works in *opposition* to the
amplitude differences created by the microphone orientation.
It's probably not an absolutely fatal flaw -- 1cm represents only
about 30 microseconds of time-of-arrival difference, and I"m don't
know enough about psychoacoustics to say whether that's enough to
cause a perceptible difference, but still. It's easy to see why they
designed it the way they did -- a true laterally coincident
arrangement would require the capsules to overlap, which would eat
more depth (although the Zoom recorder manages to do it correctly).
In any case, I wonder if this design might partially explain the
rather disappointing spatial imaging performance of the Sonys in my
recent tests.
-matt
mab blogs at http://www.crypto.com/blog/
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