The waveguide is the 7" elliptical from Parts Express, #270-316. I used fourteen drivers for the worst possible reason; I wanted people to gasp in astonishment (WOW!!!) when they first saw it. I succeeded, but nine, ten or twelve would be a more practical choice, both in terms of a more manageable size and the fact that 7'4" is too tall for the typical listening room where your listening chair is less than 10' from the speakers. If you wanted the woofer array to be arranged symmetrically above and below the tweeter you would have to use ten (3-3-4, with the four consisting of the top two and the bottom two woofers, giving you 8.7 ohms nominal impedance) or twelve (3-3-3-3 or 4-4-4), yielding a nominal impedance of 6 ohms or 10.7 ohms.

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