I would appreciate an explanation of this. If I may say so, I do
not believe it. There are not enough degrees of freedom to record
the transient arrival times. One only has four degrees of freedom
from the four microphone pickups.
How does anyone think that this is enough to record a soundfield
in the neighborhodd of a point?
I do not understand this nor do I understand the remark about
the planar wavefronts--which is exactly what speakers at
distance are producing to a good approximation.
To my mind it makes not much sense to suppose that the first order
reconstruction is correct in a neighborhood of the listener
but higher order is correct in a larger neighborhood--not literally
correct. This seems "metaphysically" impossible. Where in the
set up is there any length scale? What would determine the
size of the neighborhood? Within a given error, I can see it.
Or over a certain frequency range this might work within allowable
error limits(ie where the head shadowing works out right)
But surely no one really believes that the playback is perfectly
correct around the listener and then at a little greater distance
it is not? This defies all credibility in mathematical terms.
No relatively simple physical process produces exactly a correct answer
over a small interval and then suddenly does not over a large interval.
(Functions which are 0 over a region of space and then are not 0
elsewhere of course exist mathematically but they do not turn up
in physical problems very much).
Incidentally, Blumlein did not think it worked either. That is what
"shuffling: is for as I understand it.
I realize that Blumlein stereo is not horizontal Ambisonics because
the omni pickup part is missing.
Robert
PS I would really like to know who people think that six speakers can
comine to produce a hard transient with high frequency content. at one
ear at one time and at the other ear another time in a way that would
be stable with respect to head movements. This does not seem possible to
me in practice. (With clamped head listeners one could do it--but I do not
see how it would arise from the four signals of B format)
On Fri, 26 Apr 2013, Sampo Syreeni wrote:
On 2013-04-25, Robert Greene wrote:
Namely if a hard transient occurs say 30 degrees left of center, the
associated wavefront arrives at the left ear before it arrives at the right
ear.
Except that what arrives at your ears at first order has absolutely nothing
to do with a planar wavefront. It works, alright, but not because it has too
much to do with how the transient started out with.
--
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
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