Sampo Syreeni wrote: > the problem is squarely in that the higher order components can't be fully >suppressed
Exactly. We can model the W output as being composed of a zeroth order (monopole) component plus a quadrapole component, which is frequency dependant. A quadrapole has a squared proximity effect, so for very close sources the proximity effect due to the quadrapole becomes significant relative to the desired zeroth order output. Not something that one would expect from an omni microphone! ----- Original Message ---- From: Sampo Syreeni <de...@iki.fi> To: Surround Sound discussion group <sursound@music.vt.edu> Sent: Sun, July 24, 2011 9:40:39 AM Subject: Re: [Sursound] the recent 2-channel 3D sound formats and their viability for actual 360 degree sound On 2011-07-24, Fons Adriaensen wrote: > In a normal SF mic the effect could become significant if the distance > between >the capsules is a non-trivial fraction of the source distance AND of the >wavelength, so not really at low F. Does that really matter, though? I mean, by definition XYZ contain particle velocity (or time integrated pressure gradient, whichever you prefer). With a near source, that already ought to show the proximity effect as long as the mic does anything remotely ambisonic. How it was built doesn't really seem to affect the results at this level. So looked at from another angle, most of the phase differences that Robert pointed to, whether because of the directivity of the capsules or because of the capsule spacing plus the following corrective filter, actually ought to be there. Otherwise the mic wouldn't be measuring velocity as at should. So in fact the problem is squarely in that the higher order components can't be fully suppressed, but fold into the mix. -- Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front +358-50-5756111, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
