On 10/11/2012 09:09 AM, Dave Malham wrote:
Hmm, just got round to looking at the Wittek/Thiele paper.
"Interesting" is right. I have the greatest of respect for both Helmut
and Gunther, but paper isn't really up to their normal, very high,
standards. Just two mentions of (higher order) Ambisonics and no
inclusion of it in the comparison table ( Table 1). No clear
indication of where the data for this "Comparison of
stereo/surround-format profiles" came from (proper studies, a guess,
references [1] and [9] ??) and, interestingly, Ambisonics (either POA
or HOA) isn't included where it would have shown up very well,
especially on the reproduction of elevation.
Some other interesting statements, for instance page 7, "Thus,
stationary-source elevation cannot practically be accomplished" -
it's been a while since i read that paper, but isn't that sentence
specifically about auro-3d?
the title seems to suggest otherwise, but i think it's not really meant
as a general overview at all.
which, as we know, is not so, _if_ you use soundfield reconstruction
techniques such as Ambisonics (or 3-D WFS, or Holophonics, or...) and
page 14 "One signal on more than two loudspeakers leads to coloration
and thus should be avoided" - just on _more than_ two speakers? That
should surely be "more than one".
well, depends. iirc, theile's argument is that a two-speaker phantom
source should be a mess in terms of spectrum, but isn't (as two-speaker
stereophony demonstrates). so for some reason, the brain is able to sort
it out. more than two correlated sources, and things go awry, e.g. L/C/R
with too much crosstalk is a pitiful mess.
Ah well, at least it would get a sufficient number of speakers into
people's homes to do Ambisonics with height with a re-jigging of their
positions ;-)
if only i had some time on my hands, i'd love to throw an ambisonic
deocoder at an auro-3d layout... it's quite sub-optimal for ambi, but
there are quite a few of those systems around.
--
Jörn Nettingsmeier
Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487
Meister für Veranstaltungstechnik (Bühne/Studio)
Tonmeister VDT
http://stackingdwarves.net
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