Rob,
The measured polar patterns of real-world microphones
are (almost) always narrower than the theoretical
pattern at high frequencies. This is less so for
figure-of-eight polar patterns than for other types,
but the problem is still there. As a result, sounds
that are centrally located will have a response that
is rolled off at high frequencies.
For large-diaphragm types, the roll-off may start as
low as 2 kHz. See the specifications for the AKG414:
http://www.akg.com/products/powerslave,mynodeid,186,pid,781,id,781,_languag=
e,ENUS,_view,specs.html
For small diaphragm types the roll-off starts at about
8 kHz. See the specs for the Schoeps Mk8
http://www.schoeps.de/E-2004/specs-mk-ccm8.html
This is, of course, not a fault of the microphone
design but rather an unavoidable side-effect of their
size.
So one thing that could be done is to use the
'Blumlein' array rotated by 45 degrees, so that one of
the microphones is facing front, and then to use M-S
matrixing to recover left and right. What this will
do is to put the frequency response errors out to the
side.
eric
--- Rob Danielson <> wrote:
> At 10:34 AM +0100 4/18/06, Antti Sakari Saario
> wrote:
> ,<snip>
> >
> >Blumlein array functions like any other coincident
> XY pair and hence
> >does not require any matrixing for deriving the L
> and R elements of a
> >stereo signal. The capsule pointing 45=FBto the left
> of the axis of
> >symmetry will provide your L signal and vice versa
> for the R channel.
>
> Hi Antti--
> If you agree that the middle is under-represented
> in Greg's recording, do you have an explanation
> why? Rob D.
>
>
>
>
> "Microphones are not ears,
> Loudspeakers are not birds,
> A listening room is not nature."
> Klas Strandberg
> Yahoo! Groups Links
>
>
>
>
>=20
>
>
>
>
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