[Gary Eickmeier]

Peter Wieck wrote:
On Wednesday, July 6, 2016 at 6:45:38 PM UTC-4, Gary Eickmeier wrote:
es, spread evenly across the region between the speakers.

But will this high direct field from those two points in space sound
the same as the live sound that was recorded? Why or why not?

Gary:

AR did this for years, and years, and years, using their 3 and 3a
speakers, and had some of the finest golden-ears of the industry
agreeing that the transition from speaker to live was seamless and
transparent. This is exactly the wrong suggestion to make as there
are any number of speakers out there capable of that task. ONE
THING!! They never would have been placed per your suggestion, that
would have been an invitation to failure. I suggest you go back in
time and look for an AR white paper on how to place speakers in any
given room - all other things being equal. The surprises you will
discover:

a) Speakers are not to be placed on the short wall of a room.
b) Speakers are placed some distance from a wall, corner or from the
floor based on a number of factors determined by the room, its size
and the nature of the furnishings. This *WILL* vary.
c) No sort of additional 'enhancement' or 'deadening' or absorption
is necessary. In other words, pretty basic placement per some pretty
basic principles is all that is necessary for excellent performance
and a clean sound-stage (which is definitely larger than a human head
in height, width and depth).

I think you are confused by the size of your listening venue and the
additional complexities that adds to the process.

Peter Wieck
Melrose Park, PA

Yes I know all about the AR experiments/ demos. It was just a string quartet
and it was recorded anechoically so that the playback room would act the
same on the speakers as it did on the live instruments. I have a copy of one
of their recordings. It was a great effort and I respect what they did, but
I can't help but wonder how it would fare today. I mean, people thought the
first Edison recorders sounded just like real.

The most real sounding playback I have heard has been in a larger auditorium
with the speakers sitting on an actual stage and playing away in stereo. One
occasion in particular was a stage magician act that used recorded sound
rather than a pit orchestra. He had two stacks of Bose 802s on each side.
When you walked in you could swear it was live music, and the reason is that
the actual room acoustics swamped whatever recorded acoustic there may have
been. So it sounded just exactly like real instruments playing in that
acoustic space.

Stereo is an acoustical process, not an "accuracy" paradigm where the object
is to get the two channels to your two ears intact, with no distortions or
room effects. To address this acoustic part of the deal, you need to study
live sound and think of it as the mainly 3 fields, the direct, early
reflected, and reverberant. If you don't physically reconstruct those fields
in the same proportions and spatial shapes in your playback, or as near as
physically possible, it will sound different from live, and different from
the sound on that recording. I am using a shaped radiation pattern that puts
out 6 dB more toward the rear than toward the front of the speakers. This
extra output energizes the early reflected field in a shape that is similar
to a typical live one, going out 45 degrees from the center line of the
speaker to bounce and fill the center and go out and back from the corner
bounce to arrive from spatially similar angles to the live situation. The
extra output causes an image shift toward the reflecting surfaces, causing
an auditory event of greater depth and spaciousness with the instruments
forming an aerial image in a plane behind the speakers, the speakers
disappearing completely as sources themselves. The speaker placement ensures
that the imaging is very even all across the front of the room, and
individual images seem like they are acoustic sources right in your room,
not coming from two megaphones, so to speak. There is no combing because the
front and rear outputs are not equal; there is no hole in the middle or
clustering of reflections or stretched soloists because of the speaker
placement, extremely important for speakers with a high reflected field.
All of these factors are interrelated and very important to the total
effect, such that if you got the radiation pattern right but screwed up the
speaker positioning, you would not observe the same effect. If you place
your speakers correctly, but they don't have anything going to the rear, the
soundstage will not "set up."

Very unlikely that experimenters or speaker companies out there would
stumble upon these highly contrarian principles all at once, so I go on
preaching to see if it might spark someone's imagination. The big picture is
that you do this image modeling for the frontal soundstage and you support
the reverberant field with some surround speakers. And yes, the room is a
good part of the deal, with acoustical properties for the reflected sound
and the larger the room the more like the size of the real thing.

Finally, as for the main objection to such a technique, we are NOT doubling
up the acoustic that was recorded because there is not a substantial
reverberant field in most domestic sized listening rooms. The single
reflection that I am using to construct the shape of the reflected field
does not make an acoustic signature, and you can absorb a lot of it as you
go back in the room with thick carpeting and normal stuffed furniture so
that you have no slap echo returning if you clap your hands. So - you have
not changed the temporal, just the spatial to make it resemble the real
thing more closely - physically - acoustically - within your room on
playback.

The speakers are then seen not as direct radiators but rather as Image Model
Projectors.

Gary Eickmeier