On 12/07/2015 02:55 AM, Stefan Schreiber wrote:
Your plots refer to an empty sphere, don't they?
no, fons' plots are about a rigid sphere with omni mikes in the surface.
Take for example the 8kHz response, which is the most directive one in
the set. It's something like 3.5 dB
down at 90 degrees. Apart from the narrow peak at the
back, that's subcardioid.
See above. We currently don't know the exact frequency responses...
the point is that you are dealing with omni microphones, and the only
directivity that you can work with other than matrixing several capsules
is the acoustic shadow of the sphere.
And? This is exactly the case here. (IRT cross in two dimensions and the
8-channel hedgehog in the described cuboid form are isotropic. All 12
microphone stereo angles are 90º. A cube is a Platonic solid, "as
everybody knows".)
stefan, i think you are confused about the fact that the hedgehog or any
other open microphone arrays employ directional microphones. the OZO
cannot, because it is a rigid sphere with no way for a second acoustic
path to each capsule.
The 'hedgehog' doesn't produce anything like that, nor
is it meant to.
It does and is meant to!
this is not the case. the eight-supercards hedgehog is not meant to be
rotated ever. it has a 1:1 mapping from mics to speakers. rotating it
will give massive shifts both in source width and timbre.
the design goal of Theile's arrays is to minimize crosstalk and ensure
well-defined decorrelation between speaker channels, not isotropy. it is
intended to produce ambience only.
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