Critic's Corner

Posted by Brian H P (A) on July 22, 2024 at 13:13:39

In Reply to: RE: An added complication is the non-linearity of the "Phenomenon of the 'Weak Fundamental' " posted by John Marks on July 21, 2024 at 07:56:50

Basic rule (for many decades before design software existed) is that the -3dB point of the baffle step is 4,560 divided by baffle width in inches. So for a 15" wide baffle, that will be 304Hz. This certainly can (and should) be refined with measurements and computer modeling, but it gets you in the ballpark at the prototyping stage. In a 3-way design, the correction can be incorporated easily into the woofer-to-mid crossover, by having the lowpass transfer function down -9dB (as opposed to the usual -6dB) at the crossover frequency, and then padding down the midrange output accordingly.

In a 2-way, many designers have had good results with a "staggered" lowpass filter: an initial 3dB shelving filter of paralleled L and R, followed by the higher frequency lowpass to cross to the tweeter. Or by simply adjusting the L to C ratio in a second order (or higher) filter, usually with an oversized L1.

Prototype, measure, listen, adjust, and repeat until satisfied.