It doesn't take a millionaire any longer. If you follow the rules of
binaural psychoacoustics you don't need to measure any HRTFs to have a
recording and loudspeaker reproduction system that delivers normal binaural
hearing cues to any reasonable standard and does not make use of the
stereophonic effect, or Ambisonic equations, but is a sort of home-friendly
Wavefield Synthesis. Like WFS the listening area is much less restricted
than that of a normal stereo system and since no HRTFs or head tracking is
involved multiple listeners can be accommodated.
The first rule is that in any such chain, there must be one head shadow but
only one and it need not be the end listener's. By head shadow in this
rule
we are just considering ITD and ILD in the frequency range where these
affect localization. Since we nod, rotate, and lean and sound goes over,
under, around the front, around the rear, etc. the ITD and ILD are quite
smeared and so the brain is used to this and can adjust to an ITD, ILD head
shadow not its own. So it does not matter how the ITD and ILD are recorded
or synthesized as long as they are normal values for a frontal or rear
stage
object and then are delivered unaltered to the ear canals. So no
personalized HRTFs so far or head tracking.
The second rule operates in the higher frequency range where it is only the
pinnae that determine localization. The rule is that in any recording and
reproduction chain there must be one and only one set of pinnae and that
set
must be that of the end listener. Since few mic arrays have pinnae,
including the Soundfield, there is seldom a problem of having two sets of
pinnae in a system. (can use most dummy head mics without the outer ears.)
So the only problem in having the remaining part of a soundfield binaural,
is in making sure that all the sound sources come to the ear from a
direction that is pinnae proper. So for example central solo frontal sound
should come from the central front. All reflections or direct sound coming
from the rear should have directional components not only for the pinnae,
but also be delivered with binaural ILD and ITD values that are not then
allowed to be altered by the listener's head dimensions.
It turns out that in the horizontal plain it is not too difficult to
provide
what the pinnae need in directionality without making any HF HRTF
measurements. So I and my converts easily obtain solid full circle
localization of direct sound in the horizontal plane from ordinary 4.0
recordings like SACDs, DTS 5.1, SQ, UHJ, Dolby Atmos, Auro 3d, etc. using
just four speakers and only a modest amount of numerical processing.
Direct
elevated sound sources can be accommodated using similar rules but that
needs more research and real music recordings to test with. Hall ambience
height is easily accommodated as is all concert hall reverb, also in a
binaural friendly way.
The rules are different for headphones or earphones, however. Lots of AES
and other papers on all this, including several on the Ambiophone 3D mic
array that anyone can copy and use to make better 4.0 recordings of live
sound.
-----Original Message-----
From: Sursound [mailto:sursound-boun...@music.vt.edu] On Behalf Of
Augustine
Leudar
Sent: Friday, November 03, 2017 3:17 PM
To: Surround Sound discussion group
Subject: Re: [Sursound] 3D Browser disco
great sound design but no cigar on the binaural front - thats really not
going to get solved until a quick and convenient way of measuring HRTFs is
designed - I have several in case any millionaires out there are interested
....
On 3 November 2017 at 18:36, Ralph Glasgal <glas...@ambiophonics.org>
wrote:
Have you tried https://cloud.aria3d.com Using a Chrome browser,
Christos Tsakostas, a Greek audio researcher produces an up to 180
degrees wide stage in the horizontal plane starting with ordinary 5.1
or 2.0 recordings and you can play your own UHJ's this way. There is
also no reason why this technique could not soon produce a full circle
of direct sound using just four speakers from 4.0/5.1 media including
Ambisonic media decoded to 4.0 which I have heard this way via DTS media.
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