In Reply to: I'm still torn on the subject. posted by Presto on December 23, 2009 at 11:07:23:
"One thing for certain, dialing in "textbook" filters with no regard for driver rolloffs (actual measurements on baffle on axis) is a quite common method for many DIY active test-pilots. We have these guys offering their "dial it in an run" systems as examples of active systems when there is a whole lot more to it in fact. In fact, setting up an active system has ALL OF THE SAME steps as designing a passive equivalent, except for maybe less attention to net-resultant impedance after equalisation and impedance compensation is done"
The final "crossover," whether active or passive, is a COMBINATION of the electrical transfer function of the filters and the acoustic response of the raw drivers mounted in the cabinet. A "standard" active crossover, which produces LR4 electrical slopes at a set corner frequency, but fails to take into account the individual driver responses, will NOT necessarily result in an LR4 acoustic crossover with flat summation between drivers. To be truly effective, an active crossover must allow the corner frequencies, order, and Q of each slope to be set individually, so that in combination with the driver responses you get the desired slopes. You also need to be able to EQ out bumps and dips in the responses of each driver, at least two octaves into their stop bands, and to apply the proper degree of "tilt" for BSC. All of this requires as much measurement and modeling as a passive crossover, if you are to get the desired results.
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Follow Ups
- Thanks for pointing this out - caspian@peak.org 09:32:12 12/25/09 (0)