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From: drm2@mvuxn.att.com (David R Moran)
Newsgroups: rec.audio.high-end
Subject: Re: Speaker stands  for Monitor Audio RS952
Message-ID: <5869@uwm.edu>
Date: 23 Aug 90 13:20:16 GMT
Sender: news@uwm.edu
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Approved: tjk@csd4.csd.uwm.edu

Stands are in general the worst thing possible to do with a pair
of speakers, because almost invariably they put a broad notch
in the 100-400 Hz range due to the floor-bounce cancelation.
This is the voice range, on both sides of middle C. The sound
often "opens up" and people like it and mistake it for accurate
reproduction. It is perhaps the most common error regarding
speaker placement. The notch is commonly called the Allison
effect after its chief "documenter" (who designs around it
with extreme cleverness in his own speakers; I have no connection
to that company).

The only way around this is to be sure that the newly "standed"
distance from woofer center to floor is _maximally_ different from
its two distances to front wall and side wall for each speaker
cabinet.

In other words, if the woofer on its new stand is 22" up, ensure
that it is nowhere near 22" from the side and front wall.
The geometric-mean way to reckon "maximal difference" is with
C-squared = AB for the three distances involved, with A,B,C not
equal of course.

Doing this will let you use stands and still not have bad 
Allison-effect ripple in that crucial reproduction sonic area.

Otherwise leave them on the floor and tilt them backward a bit to
aim the tweeter more toward your ears. The "least-cubes" geometric-
mean rule still applies, however; it's just easier to achieve
with the woofer center only a foot or less from the floor....

JG Holt in Stereophile reviewed an Allison speaker a few years
ago and initially found its accurate "fullness (richness)" in
this range to be awfully weird and almost puzzlingly objectionable;
after a while he concluded (and wrote) that this was correct and
all other speakers incorrect in this regard. Not that Spile has
gone on to recommend Allisons ever, for some reason....