[Donald White]

On 4/22/2013 7:34 AM, Gary Eickmeier wrote:
KH wrote:

Keith -

Thanks for an interesting discussion - once again - I know that we both care
very much about this subject, so I hope you will stay with me for a few
excruciatiing further comments


That's ONE of the problems, yes. An integral part of which is the
lack of ability to *record* "radiation pattern". This is the essential
predicate to re-establishing the same radiation pattern on playback
(were we physically/mechanically able to do so). And, we don't.

OK, but, as you saw previously, we can synthesize, or approximate it on
playback

3-D pattern, 2-D signal.

While I have read this news group for some time and Keith can surely
answer for himself, I don't think the 3-Ds he is referring to are
spacial dimensions. The three are time, amplitude and direction. Of
these the microphone captures only time and amplitude which are are the
contents of the 2-D signal.

Don


Back into the D's for a minute: We don't usually record height, because that
is not real important in most music. It is just the width and depth that I
am concerned with. The width part is obvious, but the depth, as AE has
mentioned, is more of a learned response based on the loudness and sinking
back into the reverberance of the recorded room. However, we also
"synthesize" the depth part by placing the speakers in our 3D space of our
room, well away from all walls, and then - in my concept - by reflecting a
large part of the output from the front wall of the room. This has to do
with how sound in rooms differs from sound outdoors or anechoically. When a
source is played in a room we get a lot more information about its
localization than if we had only the direct sound from that source. The
reflection patterns set up a sort of XYZ coordinate on the sound event that
gives an auditory event more information to go on, especially if we can move
around, turn the head, etc. Short version - we can tell if the speakers are
out into the room in OUR 3D space or up against the wall.



If we could RECORD using techniques that would capture all of the
information needed to reconstruct the identical frequency response,
radiation pattern, locations, and sound pressure, AND you could
create a speaker system with the identical radiation pattern as the
piano, THEN:

It would sound very similar, not the same. You could likely make it
sound identical within the limits of listener perception. The
prerequisites, however, are daunting to say the least.





Constrained to the *original* venue, with a single instrument. If
that player piano was in my living room, it absolutely would sound
like a completely different performance than the original. This is a
very real constraint that is highly variable, and outside the control
of recording engineers and speaker manufacturers.


You said above "...if we could figure out how the piano makes sound
into the room - what frequency response, radiation pattern, direct to
reflected ratio, and so on,...", but that's not even a fraction of the
problems in implementing your model. How do you record the radiation
pattern? How do you design *A* speaker system with the same radiation
pattern of each recorded instrument (or orchestra)? How do you
control for vastly different listening rooms?

OK, true enough, but should that stop us from pursuing an improvement, an
enhancement to the playback that could make the limited info in a commercial
recording sound more real, more like live music?

All I was trying to establish with the tautology was that the spatial nature
of the original is an important, AUDIBLE part of the reproduction problem.
One that perhaps has been ignored in conventional stereo theory - you know,
the diagram of how stereo works that shows just two speakers and a head, in
an equilateral triangle.

In the model of reproduction that I want to mimic the live model more
closely, we are simply making an estimate, an educated guess, on the most
important parts of what a typical live sound field's spatial nature is like,
and trying to get closer to that in the reproduction. The answer to AE's
questions about recordings is that only the best recordings contain in
addition to the direct sound from the orchestra the early reflected and a
touch of the reverberant sound of the venue, just enough to give your
playback the "sound" of the original if you can somehow array those recorded
sounds spatially in your own room in a similar way as in the original. If
the engineer had recorded only the direct sounds by close-miking everything
then there would be no real space in the recording. He might get away with
synthesizing it electronically, but we would probably be onto him with the
best playback systems.

In my big theory about how exactly to build the playback model, the
positioning of the speakers is very important so that the stronger reflected
output will be more of a neutral canvas on which the recorded reflected
sound can be arrayed, or painted, if the recording contains these delayed
signals. If it does not contain them, the model does NOT make fake ones as
you seem to be suspicious of. That part is very hard to explain to people
the first time around, but believe me, I do not like synthesized electronic
enhancement of any sort to "fake" a night club, rock arena, concert hall, or
anything else. EVERYTHING in my playback model comes from the recorded
signals, the attempt being to just present this more realistically according
to what we know about sound in rooms.

And the biggest problem? It's "who cares?". We are a dying breed if
you hadn't noticed, and IMO high-end music reproduction likely won't
outlive us. There is simply no market for "better stereo" that would
have to be re-imagined, and would have to start at the recording
stage.
There are major compromises necessary at every stage of the recording
and reproduction process that preclude, with current technology and
methods, doing what your model suggests. These compromises affect all
of us. We choose to focus our attention on the areas of reproduction
that are most important for our enjoyment, and our sense of realism.
You clearly think "spaciousness" is paramount, and you forgive many
less realistic attributes (faults in my model) of systems designed to
synthesize that spaciousness.

I hear you! And I hope everyone realizes that my ideas are of interest only
to those of us who are after this ultimate reproduction experience, and that
our wives and children may not care or even perceive any of it.

Your blind spot in this argument reminds me of something one of my
family members (a Jazz saxophonist) told me "People who don't like
Jazz, just don't understand it". Like her, you can't accept that
anyone who understands your "theory" could possibly disagree with
you. Sorry, but that just isn't the case. And no, I don't like Jazz.

What you presented as Logical Tautology was actually a grammatical
tautology.

Keith

Well, if you could give me just a teensy bit of credit that I do not
actually have a blind spot to any part of it, because I have been studying
it for some 30 years, doing it in my own system, and trying to find fault
with it, but it holds up to everything I have read and heard. I know full
well that it is hard to explain. I had to read the original Bose research
paper a couple dozen times before I understood it, but I finally "got" the
point about the difference between the spatial and the temporal and was able
to separate those out in my mind and use them in my tale. The readers of my
paper at the AES could not understand that, and like many others were
confused by the difference in size between a home listening room and the
real concert hall, saying that the model couldn't work because of that
difference. That is the hardest part to get through, they not seeing that
they have the same problem, but that they can still do something about the
spatial part to make it sound better, then address the physical size part by
simply building a bigger listening room!

As I asked Arny Krueger to do, it is possible to analyze all of the parts of
the listening experience - the audible parts - and examine just what is
happening to them as we translate this experience from the redording to the
reproduction. If we could get all of the spatial, spectral, and temporal
aspects of the experience to be identical, then we would "be there." And you
are correct, we cannot do that in the field-type system, but it is for
acoustical reasons and not so much about not being able to record full
periphony or all of the directional effects with sufficient channels.

Gary Eickmeier