"Arny Krueger"

Now for the seriously damning facts about the Bose 901. When the 901 was
built, not that much was generally known about optimizing the performance
of
arrays of small drivers. It turns out that arrays of small drivers can be
a
real can of worms, if smooth, well-balanced frequency response is desired.
I'm quite sure that if Bose were to design the 901 today with a clean
piece
of paper, they'd do it quite a bit differently.


** What - you mean there is an even " cheaper " way than the one used
now ;-)


Probably the most serious problem with designs based on ad-hoc collections
of identical small drivers is that they can have very rough frequency
response (lobing and comb-filter effects) when you move slightly off-axis,
and they can also have frequency response that is a strong function of
distance from the speaker to the listener. There are ways to manage these
problems with generally involve putting the drivers on curved baffles,
and/or adjusting the level and/or frequency response of the drive to the
various drivers. However, the classic Bose 901 design really does neither
of
these things well.

Here's an AES paper that points out these problems and potential solutions
in some detail:

Author(s): Keele, Jr., D. B.
Publication: JAES Volume 38 Number 10 pp. 723·748; October 1990
Abstract: The Bessel array is a configuration of five, seven, or
nine
identical loudspeakers in an equal-spaced line array that provides the
same
overall polar pattern as a single loudspeaker of the array

One important point is that the no way is the Bose 901 a Bessel
array.
A second important point is that of all the Bessel arrays analyzed, 5
drivers in a row was found to be the only one that was recommended.


** Hang on Arny, what multi driver array has the 901 really got ?????

The answer is none. There is only ONE driver facing the listener.

You are mixing the 901 up with the 802 PA speaker.




.......... Phil