[Gary Eickmeier]

ScottW wrote:
On Apr 26, 12:16 pm, George Graves wrote:

First of all, there's nothing "forgotten" about real stereo.
Many record companies still record that way, but usually, mostly for
classical music. Scott have you ever even heard a real stereo
recording played back on a decent system? It sure doesn't seem so.

I guess my Linkwitz Orions or my Maggie 1.7s or my recently deceased
Quad 63s or my Legacy Focus based surround system must not be up to
the task. I'll have to just enjoy "unreal" stereo which fortunately
for me...still seems to have depth and a 3D quality for my music
pleasure.

Your system has depth and a 3D quality? Then why were you fighting everybody
tooth and nail about all this?

I think I need to re-clarify a few things to tie up this thread and get back
to the main point about stereo. Some have asked the musical question, how
can stereo record height, width, and depth if the microphones can't know
anything about direction, or how can all of this spatial information be
contained in any recording? There is no HRTF or head shadowing in a
recording. It just can't work.

But it does. I have tried to put across the major, major concept that
stereophonic is not a head-related system, the recording of ear signals in
any way. There is no HRTF or head shadowing because those concepts have
nothing to do with stereo, just binaural. We do not need to "encode" all of
the sounds arriving at the microphones to be able to tell direction of
anything, because it doesn't work that way.

Harry Olson defined stereophonic as follows: "A stereophonic sound
reproducing system is a field type sound reproducing system in which two or
more microphones, used to pick up the original sound, are each coupled to a
corresponding number of independent transducing channels which in turn are
each coupled to a corresponding number of loudspeakers arranged in
substantial geometrical correspondence to that of the microphones." William
Snow comments that "it has been aptly said that the binaural system
transports the listener to the original scene, whereas the stereophonic
system transports the sound source to the listener's room."

I hope all that comes as a shock to some readers. The Cliff Notes version of
stereo theory is this: We record a set of sounds. We play those sounds back
on speakers that we PLACE in our listening room where those sounds belong.
There may be three speakers up front. They will have a certain height, such
as the ear height of the listener sitting down. They may be pulled out from
the walls and encompass a certain lateral spread. This is where the width
and depth come from. In addition to the physical depth we perceive by simply
pulling the speakers out from the walls into 3D space, there is a
psychoacoustic depth contained in the recording due to loudness attenuation
and sinking into the reverberance of the recorded venue. Finally, and the
hardest to understand, we can bounce some of the output of the speakers from
the surfaces of our room in order to use the acoustics of the room to help
build a real space around the recorded sound. In a properly set up system
this effect can actually decode, or paint, the recorded reverberance onto
the appropriate walls of your listening room.

Even shorter version: How does stereo know where the sound came from?
Because we PUT it there, in front of us, where it belongs. The sounds that
we hear in the reproduction are real, physical sounds that exist in real
space in front of you, you hear them with your natural hearing, your own
HRTF and head shadowing, a summing localization permits auditory events
anywhere along a line between the speakers, and the recorded space gives the
presentation the "flavor" of the original space if such is contained in the
recording.

All of this was well known by the pioneers at the Bell Labs who were doing
the experiments, but of late it has become confused with binaural with some
thinking that what is wrong with stereo is we need crosstalk cancellation,
or we need to record the HRTF, or head shadowing, or anything else that has
to do with binaural such as Sonic Holography, Holophonics, Ambiophonics,
Transaural - there are a number of these that keep popping up about every 5
years, some new genius (usually a rocket scientist who is here to straighten
us all out) comes up with a new form of loudspeaker binaural.

Gary Eickmeier



ScottW