Douglas Wolfe got it right. The principle of the pipe organ is the resonance of a column of air at one frequency. That is why there are so many different sized pipes. Each produces a different tone. The longer the pipe, the lower the frequency of the tone and visa versa.

The principle of the Bose PAS is using a line array (a column of speakers) to radiate sound in such a way as to approximate cylindrical pressure waves. That's in contrast to spherical waves which are typical for most speaker systems. With true cylindrical waves the sound intensity decreases as a linear function of the distance from the speaker. With spherical waves it decreases as the square of the distance. The result is that with the PAS cylindrcal radiator the sound intensity is much more uniform throughout the area surrounding the speaker, as has been reported by those who use the system. Since the very low frequencies are essentially non-directional, they use a sub-woofer to handle the low end of the frequency spectrum.

Line arrays are not new to the world of acoustics. They have been used in various types of sonar systems (underwater acoustics) for a number of years. Bose has taken a well known physical principle and successfully applied it to the audio spectrum.
Paul C.