[Gary Eickmeier]

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

Peter and Scott -

OK you've got me. I am using a trick processor that is super secret - or
was, until you guys exposed me. It functions as a spatially arrayed,
spectrally shaped, temporally delayed sound field simulator. It took about 5
months to construct from plans that I gave my builders when I built the
house. Well, as long as we're here, let me describe how you can build one
too, to check my results on your own. Maybe it will sell.

When we built my media room - combination audio and video - I specified a
rectangular space 20 by 30 feet, with cathedral ceiling and specular
reflectivity at the speaker end. When I installed my speakers I placed them
exactly 5 feet out from the side walls and an equal amount out from the
front wall. The speakers have a negative directivity index, putting out 6 dB
more sound in the reflecting direction than toward the listeners. This is to
feed the simulator more of the sound than goes out the front as direct sound
from the recording.

The simulator then takes over the processing. The speakers face diamondwise
into the room, the four driver faces aiming at 45 degrees from the center
line. The rear radiation thus goes out toward the front wall with a
vengeance, half of it going toward the other speaker and half of it going at
a 45° angle toward the corner of the room, whereupon it gets reflected, or
processed, to come from the adjacent side wall with a certain delay and
wider spatial angle than the direct sound from that same speaker. In this
manner the sound gets processed so that it comes from spatially similar
angles to the live sound that was recorded and the soundstage takes on a
width and depth that it wouldn't have unprocessed.

I call the mechanism of my processor "reflection" and the whole idea of
doing it this way "Image Model Theory."

So, Scott, even though you can't hear angles, architectural acousticians
have been designing concert halls to do this same process to the live sound
for years and years. Please don't tell them that we can't hear angles
because they think (and I agree) that the spaciousness brought out by the
reflected sound gives the music a pleasing effect and they actually strive
for it in their designs. Peter, so right, now you know the mechanism of the
additional levels of processing. The only question remaining is do they
record any of the early reflected sound, or ambience, while recording the
direct sound of the instruments? Nah - impossible - they shut the
microphones off well before all of that reflected sound can reach them,
thank God.

We can't hear angles anyway.

Gary Eickmeier