[Scott Dorsey]

Gary Eickmeier wrote:
I know what standard stereo theory says.

No, no you do not. You seem to believe some very strange things about
"standard stereo theory" that nobody else has ever heard of.

What I am trying to say is that
this is not correct, or at least not complete. The simplest example is a
single impulsive sound followed by its reflection a few milliseconds later.
Unless the reflection is heard from a different incident angle than the
direct sound, it will not sound like the original (forward masking).

The ears can't hear the actual angle that the wavefront is coming from, it
can only tell the amplitude and phase differences between channels. So if
the reflection has different amplitude and phase differences than the original
impulse, it has _perceived_ as coming from a different angle. This is how
imaging works.

Until you understand this, you are going to continue to be in the dark.

For
example if this were done in an anechoic chamber and you had two speakers
doing it, one straight ahead and one off to the side, you would be able to
hear a certain amount of spaciousness contributed by the reflection. But
bring the reflection speaker around to the same position as the direct
speaker and it will not be the same.

Correct. This is not sterophony, this is two sources both producing
uncorrelated signals. Stereophony is different.

In order for us to hear the multitude
of reflections contained in a good recording, we must make those delayed
sounds come from off to the sides. This can be done with some extra speakers
on time delay or, much simpler, just reflect some of the speakers' output
from front and side walls. If this is done within the fusion time (as it
always will be in small room acoustics), then it will lend a spatial
broadening effect with no "echo" as such.

This is true, but unfortunately the reflections added by the playback room
are always the same no matter what recording you play. Consequently, if
the room reflections are dominant, it makes everything you play back sound
all the same. This is interesting but not particularly useful, and it also
has nothing to do with stereophony.
--scott


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"C'est un Nagra. C'est suisse, et tres, tres precis."