The Problem with Stereo
Please note the interpolations.=20
But, first a few things. I thought my main listening room was large at 17 x=
22 x 10 feet. But, 20 x 30 is as large as many intimate performance venues=
, and as such has some greater possibilities for spatial performance than a=
smaller venue. And, as apparently, that room has designed reflective prope=
rties and (I am sure) controlled surfaces with carefully designed ceiling a=
ngles, this would be even more so.=20
In a sense, this is not 'fair' to the general premise as such a room would =
swallow up many speakers and many electronic configurations as it would sim=
ply be too large to be filled by a typical system.=20
On Monday, July 4, 2016 at 5:57:58 PM UTC-4, Gary Eickmeier wrote:
Scott wrote:
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"Gary, we know what you've been doing. You have told us about it many
times. You like your stereo bounced off the walls of your listening
room. You find it pleasing and that is completely fine. I have heard
the Bose 901s on several occasions including a couple of demos set up
by Bose themselves in custom rooms built just for the 901s. It wasn't
to my liking. Not one bit actually.
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Not talking about 901s.
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I already explained what it is you are actually hearing. Temporal
differences between your two ears. If you think you can actually hear
angles without the temporal differences put it to the test. See if
you can still "hear angles" with one ear blocked so your brain does
not receive the temporal differences.
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This is some of the crazier statements that you have made Scott. Still no=
t=20
sure which Scott you are - but can't hear angles? All of a sudden we can'=
t=20
hear in stereo? What kind of nonsense is this? Where did you get it?
I think this is a careful interpretation of Scott's statement. I read Scott=
's position as that the brain adds the perception of angles and locational =
information to the interpretation of sound based on the fact that the infor=
mation is delivered as part of the process. The violins on the left of the =
stage have angular information as recorded that is different from the percu=
ssion to the rear or the larger strings to the right. And this, the ears vi=
a the brain interprets as spatial relationships. One ear is akin to depth p=
erception with only one eye. Just possible with large amounts of practice (=
one-eyed people can learn to drive safely, climb stairs and other sorts of =
activities that typically require spatial perception). But, it is not a ski=
ll that normally-sighted (or eared) individuals need to cultivate.=20
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No doubt reflected sound/ hall acoustics has a profound effect on the
sound quality of live acoustic music. But the spaciousness is real.
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Yes, and it needs to be real on playback as well.
No, not really. The brain does a pretty good job of adding the information =
based on temporal clues. HOWEVER - in a room as large as the one described,=
most speakers would simply not be up to the task of providing those cues w=
ith sufficient acuity as to overcome the other issues (size and such) inher=
ent to the room. I am not even sure my Maggies could do it even with my 200=
watt amp. So, there would be a "problem with stereo" in that venue, for su=
re.=20
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The separation of instruments in a live concert is due to...the
actual separation of instruments in a live concert. Think about it.
There is a whole science behind concert hall design. It's something I
find quite interesting and have done a fair amount of research on. It
does not apply to stereo playback rooms. They are entirely different
beasts and serve very different purposes. On top of that much of what
we perceive as "imaging" and "spaciousness" at a live concert is due
to visual cues. We don't get visual cues in stereo playback. If you
could get the same exact sound in the playback room that you got at a
concert hall the perception of imaging would not sound "right" and
would be deemed inadequate.
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No, they are not different. If you don't reproduce, or reconstruct, the=
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spatial realism it will sound different.
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Yes, it will, and yes, it does. Unless - think this through - the actual re=
cording uses a single pair of microphones separated by the approximate dist=
ance of human ears, with some pretty heavy insulation between them and some=
pretty special reflector devices around them, they are only an interpretat=
ion of what any individual hears in a concert venue. And front-row-center D=
OES NOT sound like second-balcony-restricted-view. Nor, even, 12th-row-cent=
er.
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Reflected sound is recorded along with direct sound with most
traditional stereo recordings. It's already there and is brought out
quite nicely with a well designed stereo system in a stereo room that
is not plagued by a lot of reflectivity. No need to double up on what
was already recorded at the concert hall. It only creates spacial
confusion by presenting spacial cues from two different spaces on top
of each other.
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You would be correct if we were talking about binaural systems. Stereo is=
a=20
field-type system. Do you know the difference?
"Stereo" is a recording of a sound field via point-sources, mixed into a bi=
naural signal delivered electronically and separately to two separate point=
s. What happens from there is a combination of the speakers, the room, and =
the engineer's idea(s). However it is sliced and diced, that is what 'stere=
o' is.=20
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My message is simple: When both ears are free to hear all sound fields in=
=20
front of them, the system is not operating binaurally. Stereo does not wo=
rk=20
by piping the two "signals" to the ears, it works by recreating sound fie=
lds=20
in rooms.=20
No, that would be headphones. Funny thing about headphones - they get _exac=
tly_ the same signal as speakers do - they just have less confusion around =
them what with walls, glass, floors, rugs, space, position and such. Expect=
ing a room to behave as headphones is silly.=20
Those fields must have the same spatial characteristics as the=20
live sound. The most efficient way to reproduce the early reflected field=
is=20
by reflection. If you do this with the speakers positioned in a certain w=
ay=20
and with a certain radiation pattern the imaging will be improved and the=
=20
spaciousness and depth will be reproduced. If you do it by directional=20
speakers with sound killing in the room you will be folding the early=20
refected field onto the direct field, destroying the spaciousness that wa=
s=20
recorded.=20
Neat trick if it can be done. Point being that a room is NOT a concert venu=
e. When, under controlled conditions, they are both the same, then there re=
ally will be no issues between speakers and live performances. AR (and othe=
r speaker makers) proved this contention over and over through the 1980s. O=
utside of such controlled conditions they are NOT the same.=20
It will sound like double mono.
YIKES! Double-mono. Not hardly. I don't think that in 40+ years of ditherin=
g around this hobby I have EVER been in a room so awful or with equipment s=
o poor as to confuse any sort of monaural signal with any sort of stereo si=
gnal - well, perhaps the time I met with a pair of Bose 901s - it all sound=
ed like mud. Stereo/mono, but still mud.=20
All of this should have been=20
obvious to you after a certain number of years of listening to speakers o=
f=20
various radiation patterns. Can you hear differences among box speakers,=
=20
dipoles, bipoles, omnis? Good. Those differences are caused by difference=
s=20
in the image model, or reflection patterns and strengths, among those=20
speakers. Study that for a while.
Those differences are, in fact, due to the systems you describe. But as per=
ceived by the ears, the differences are entirely temporal when they are NOT=
due to differences in performance curves and placement. A Cerwin Vega spea=
ker with a 15" woofer, no audible midrange and a highly directional tweeter=
is an entirely different species than a Klipschorn or a high-end Maggie, o=
r an AR9, or a KLH 11.=20
I think your listening room allows you to cure a problem that is not releva=
nt to most of us, to your pleasure and advantage. But what applies there do=
es not necessarily apply elsewhere.=20
Peter Wieck
Melrose Park, PA
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