"Gary Eickmeier" wrote in message
...
Serge Auckland wrote:

I quite liked the 901s for their frequency response and perceived low
distortion, although with the 11% direct, 89% reflecting system, they
wouldn't image properly whatever you did. Nevertheless, they produced
pleasant sounds with a high-power amplifier behind them.


The imaging part is wrong. Bose 901s are how I learned about imaging.

I was stationed in England, where the houses have bare plaster walls. I
had positioned the speakers in my normal, stupid way (near the walls and
wide apart, according to the manual, which is another story), and I tried
to hear this "imaging" thing that the blokes were describing in their hi
fi magazines. I had to admit, center soloists sounded 6 feet wide, and I
couldn't "place" anything. I was about to give up and go listen to some
Quads or something, when I decided to go wild and experiment with
placement. The British always talked about placing them well away from the
walls, and about 1/4 of the room width apart, so I tried that, and... I
was so floored it started a series of letters to Bose on why the manual
didn't identify this. I could now hear a pinpoint center soloist floating
midway between the speakers, and the rest of the instruments were
locatable, and the DEPTH! Holy ****! I realized immediately what causes
the depth impression in stereo - the reflected sound from behind them!
Only it was even more obvious with a reflecting type speaker. In fact,
everything about positioning them was hyper-critical with this type of
speaker, because what it is doing is establishing a network of real and
virtual speaker images that combine to form the frontal soundstage, and
when you got it right, it beat the crap out of everything else, because
the other speakers could not use the reflected, or virtual speakers, as
effectively, so you would get a rather flat, compressed soundstage
compared to the 901s.

The letters impressed Dr. Bose so much that he called me (in England) from
Massachussetts, just to explain a few things about acoustics and speakers.
We talked for an hour. I was, of course, very ignorant about this stuff at
that time, and I wished I could see him one more time, which I did at the
factory. I had lunch with him and had a couple minutes in the office with
him. The gist of the conversation was that I was trying to convince him to
build a new, kick-ass 901 type speaker with a few modifications in the
radiation pattern and a built-in subwoofer - some sort of new all-out
attack on the state of the art. Then to take it around to the audio shows
like they did with the 901 - do you guys remember the slide show
demonstrations they did? He said that if I needed anything more than a
901, they had the professional line, and he would have his secretary find
me a catalogue of those. But his decided bent was to make speakers for the
masses, not for the audiophiles, who make up less than 1% of the market.

My recommendation for speaker placement, any speaker, but especially
these, is 1/4 of the room width from the side walls and an equal distance
OUT from the front wall. This establishes a lattice of real and virtual
speakers that are all equidistant from each other, forming the most solid,
evenly spaced, deepest, and widest imaging possible. Reflecting type
speakers enhance this effect, and direct firing speakers benefit from it
as well, in that it will extract whatever depth and spaciousness they are
capable of - but notice, the reflected images of this type of speaker will
not have a flat frequency response, so their contribution will be muted by
the amount of directionality. That is why Floyd Toole's project on speaker
preference showed preference for wider radiation patterns with more even
response at the edges. Also why Mirages, Quads, MBLs, etc have much better
imaging than most.

So I am in hog heaven with my 901 setup in my 21 x 31 ft room, with subs,
and surround sound, but it is right next to impossible to communicate all
this to the world at large, because regular people couldn't care less, and
audiophiles don't like 901s.

Gary Eickmeier

Actually, Gary, I bought a pair in 1970 and had an excellent setup, with
mahogany wood paneling behind them, set up about the way yours were, and
with equally convinging imaging. Then I went and added a Dynaco Quadapter
and a pair of little ADC bookshelves for the rear...and was in simulated
Quad heaven for a short period. But a divorce and a move to an apartment
ended all that, and in that apartment stacked Advents fit and sounded
better.

I have been able to build convicing 3D soundstaging by playing with
positioning and reflective room characteristics with almost any speakers I
have had...but I have also learned that really good speakers (from a
dispersion standpoint) do it better than others....that's one of the
reason's I like the Thiels. And now, with five full range Thiels in 5.0
configuration, I can get rock solid and deep-as-hell soundtaging with
virtually no reflectivity (take a look at my speaker setup on Audio Asylum
under "theaudiohiffle" to see what I am referring to, if you so desire). So
what was very important for stereo is much less so for surround, IME.