> For single MS, I use SpectraFoo to compute the delay between between the M
> and S microphones ad try to adjust their positions so that is 1 or zero
> samples. Perhaps that is overkill, and maybe say an overlap of 0.5cm can be
> achieved for taping overlap (giving a coincidence error of .25cm either side
> of the S capsule) would not be too bad? A full wavelength at 10KHz is about
> 3.4cm but I would think even a quarter wavelength non-coincidence is going to
> give some significant effects (.85cm)?
Ray,
I did some experiments for a stereo article, and with white noise bandpass
filtered around 1kHz, 3 samples were about the minimum to produce a stereo
shift. However, at a path length difference between two mic capsules,
equivalent to 3 samples (23mm) the first extinction frequency is about 7kHz,
so that is more of a priority with a multiple mic rig than stereo placement.
It depends on what you are recording, but you may well get away with a
"notch" like that within a stereo image as there are larger effects in many
commercial stereo setups - ORTF for one example. That works as our ears
"interpret" the effect, but with sum and difference matrixing as with double
M/S, it may show up at important directions.
What are you going to use as the fig-8 element for the double M/S? The
problem with the MKH30 is that it is end-on and will thus stick out
sideways.
David Brinicombe
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