Posted by JLapaire [ 63.76.208.41 ] on January 12, 2004 at 07:09:48:

In Reply to: Directivity and bass cabs posted by Mike.e on January 09, 2004 at 22:06:44:

Augsperger's cardioid looks very much like what Meyer is doing. A second driver 34" behind the first, inverted and delayed, produces the rear null. Within the cabinet, the rear driver might be assisting the front driver like a push-pull in spite of the delay.

Would a U-shaped baffle with the leg length chosen for 1/4 wavelength also exhibit a cardioid pattern or at least a dipole pattern with reduced rear projection?

In any case, it looks like progressive cancellation at low frequencies is going to nix the use of open-baffle types for DJ use where weight and bulk are important considerations. I might try some in my sunroom where room modes are a problem and high SPL not necessary.

John

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