[Scott[_6_]]

On Friday, July 1, 2016 at 7:37:29 PM UTC-7, Gary Eickmeier wrote:
Peter Wieck wrote:
On Thursday, June 30, 2016 at 7:45:42 PM UTC-4, Scott wrote:


You can't separate them. Spacial perception heavily relies on
temporal character of sound. You can't "hear angles." You can hear
temporal differences between the right and left ear in sound coming
from an angle which your brain will process as sound coming from an
angle. Spacial perception relies on temporal information.

Thank you for writing in few words what typically takes me many. Must
be the German in me - never use one word where three-or-more will do
better.

But the point of all this is that how sound is delivered in a
listening room from linear motors driven by electronic impulses is
nothing like what happens in a concert venue, unless the instruments
are electronically reinforced (which is not uncommon in these
troubled times). The sound is some analog of the original noise that
has been processed (engineered) into a shape to be delivered via the
motors with hopefully pleasing results.

It may be possible to enable the motors to provide noise that is
'spatially' closer to the original if the room has that capacity and
the motors are capable of directional delivery and the signal is
there to be delivered. But it would require additional levels of
processing, and probably additional channels. I am not so sure
whether conventional binaural signals have that information in the
correct form. This is where experimentation under real-world
conditions will separate the theory from the actual.

I, at least, have experimented with the more brute-force approaches,
passive and active. They are best described as "interesting", but not
really something I would set out to accomplish in every venue. Often
it is distracting, for a fact, and very nearly never riveting.

Peter Wieck
Melrose Park, PA
=20
Peter and Scott -
=20
OK you've got me. I am using a trick processor that is super secret - or=
=20
was, until you guys exposed me. It functions as a spatially arrayed,=20
spectrally shaped, temporally delayed sound field simulator. It took abou=
t 5=20
months to construct from plans that I gave my builders when I built the=
=20
house. Well, as long as we're here, let me describe how you can build one=
=20
too, to check my results on your own. Maybe it will sell.
=20
When we built my media room - combination audio and video - I specified a=
=20
rectangular space 20 by 30 feet, with cathedral ceiling and specular=20
reflectivity at the speaker end. When I installed my speakers I placed th=
em=20
exactly 5 feet out from the side walls and an equal amount out from the=
=20
front wall. The speakers have a negative directivity index, putting out 6=
dB=20
more sound in the reflecting direction than toward the listeners. This is=
to=20
feed the simulator more of the sound than goes out the front as direct so=
und=20
from the recording.
=20
The simulator then takes over the processing. The speakers face diamondwi=
se=20
into the room, the four driver faces aiming at 45 degrees from the center=
=20
line. The rear radiation thus goes out toward the front wall with a=20
vengeance, half of it going toward the other speaker and half of it going=
at=20
a 45=C2=B0 angle toward the corner of the room, whereupon it gets reflect=
ed, or=20
processed, to come from the adjacent side wall with a certain delay and=
=20
wider spatial angle than the direct sound from that same speaker. In this=
=20
manner the sound gets processed so that it comes from spatially similar=
=20
angles to the live sound that was recorded and the soundstage takes on a=
=20
width and depth that it wouldn't have unprocessed.
=20
I call the mechanism of my processor "reflection" and the whole idea of=
=20
doing it this way "Image Model Theory.

"Gary, we know what you've been doing. You have told us about it many times=
.. You like your stereo bounced off the walls of your listening room. You fi=
nd it pleasing and that is completely fine. I have heard the Bose 901s on s=
everal occasions including a couple of demos set up by Bose themselves in c=
ustom rooms built just for the 901s. It wasn't to my liking. Not one bit ac=
tually.=20

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So, Scott, even though you can't hear angles, architectural acousticians=
=20
have been designing concert halls to do this same process to the live sou=
nd=20
for years and years.


Concert halls serve a very very different purpose than a playback room. Exc=
ellent concert halls tend to sound really bad with PA systems. Good acousti=
cs for live acoustic music are lousy acoustics for stereo systems. A concer=
t hall helps create the sound of the performance. Recording and playback do=
es not create it, it documents it and tries to simulate the effect. Totally=
different things.

Please don't tell them that we can't hear angles=20

I already explained what it is you are actually hearing. Temporal differenc=
es between your two ears. If you think you can actually hear angles without=
the temporal differences put it to the test. See if you can still "hear an=
gles" with one ear blocked so your brain does not receive the temporal diff=
erences.=20

because they think (and I agree) that the spaciousness brought out by the=
=20
reflected sound gives the music a pleasing effect and they actually striv=
e=20
for it in their designs.

No doubt reflected sound/ hall acoustics has a profound effect on the sound=
quality of live acoustic music. But the spaciousness is real. The separati=
on of instruments in a live concert is due to...the actual separation of in=
struments in a live concert. Think about it. There is a whole science behin=
d concert hall design. It's something I find quite interesting and have don=
e a fair amount of research on. It does not apply to stereo playback rooms.=
They are entirely different beasts and serve very different purposes. On t=
op of that much of what we perceive as "imaging" and "spaciousness" at a li=
ve concert is due to visual cues. We don't get visual cues in stereo playba=
ck. If you could get the same exact sound in the playback room that you got=
at a concert hall the perception of imaging would not sound "right" and wo=
uld be deemed inadequate.=20

Peter, so right, now you know the mechanism of the=20
additional levels of processing. The only question remaining is do they=
=20
record any of the early reflected sound, or ambience, while recording the=
=20
direct sound of the instruments? Nah - impossible - they shut the=20
microphones off well before all of that reflected sound can reach them,=
=20
thank God.

Reflected sound is recorded along with direct sound with most traditional s=
tereo recordings. It's already there and is brought out quite nicely with a=
well designed stereo system in a stereo room that is not plagued by a lot =
of reflectivity. No need to double up on what was already recorded at the c=
oncert hall. It only creates spacial confusion by presenting spacial cues f=
rom two different spaces on top of each other. This is not to say that the =
stereo recording and playback can't be augmented by distortions. It can. Vi=
nyl playback and tube electronics do this quite nicely. So much so that man=
y people confuse these euphonic distortions with greater accuracy because t=
hey often have the overall effect of greater realism. I personally find tha=
t splashing the sound all over the walls is a distortion that simply does n=
ot enhance the perception of realism nor does it sound in any way pleasing.=
If you like it that is just fine. We all get to choose for ourselves what =
we like.=20

=20
We can't hear angles anyway.
=20
Gary Eickmeier

If you can do it with one ear let me know.=20