Mind Stretchers
"KH" wrote in message
...
On 6/9/2012 2:09 PM, Gary Eickmeier wrote:
Yes, that is the problem. The signal presented to the listener, in the
venue, has angular, temporal, and level clues that, in conjunction with
the HRTF of the listener, create a spacial image. That information was
not, however, encoded into the recording except as temporal and level
information. No matter how that information is played back, the signal
reaching the listener cannot be the same as in the venue. Reflecting the
sound cannot, except in the context of listener preference, ameliorate
this constraint.
Keith, I'm not sure what exactly your conceptual problem is, but everyone
knows that stereo operates on temporal and level differences between
channels. You have noticed how those differences can cause the perception of
phantom images between the speakers, right? That spatial information is
encoded into the channels by means of temporal and level differences in the
signals.
Now, I have observed that reflecting a part of the sound from room surfaces
can cause an image shift toward the reflecting surfaces. This has a twofold
perceptual impact. One, it causes the sound to go outside the speaker boxes
and appear as an aerial image somewhat behind the plane of the speakers,
seeming like the instruments are right there in the room with you, rather
than coming from speakers. Secondly, it causes an impression of spaciousness
in recordings that contain such information, such as correctly miked
symphonies in a good hall. Most of us have experienced this very audible
difference between directional speakers and more omni type speakers.
OK, fine, now between those two types of sound, one is likely to sound
closer to live than the other. If you think that is just a preference and
worth no further study, then that is the bed you shall lie in. If I think
this is a significant point and worth further study, and try to get others
to notice these effects and help me out, then please don't tell me it is all
pointless because you are not interested. Audiophiles have been trying to
figure out what causes these effects for decades. They have complained about
boxy sounding speakers and the hole in the middle effect and wondered what
makes some systems sound more realistic than others. My theories answer some
very basic questions about very audible effects, and should be studied
further.
Yes, more psychoacoustic investigation is called for, to test these effects
of reflected sound w respect to the playback situation. No, I have not and
cannot do it all on my own. But I need some of those who can do it to pay
attention and see if some of my suggestions on speaker placement and
radiation patterns and room treatment could be true, so that it might help
engineer the installation of stereo systems and the development of new
speakers and maybe recording techniques.
It's a whole deal.
Gary Eickmeier
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