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lpd
10-24-2014, 04:44 PM
I have a pair of speakers made by a Canadian company named Waveforce that uses a JBL 2235 bass driver two 6 inch Audax mids a Dynaudio tweeter in a cabinet similiar to a L250. The JBL bass drivers are EQ with an active crossover that was custom built for the system that had a bass volume and blend or boost feature the mids and tweeters are passively EQ with internal crossovers, ala biamp two way system with active sub XO.What would you guys recommend for an active two way crossover? My understanding from researching the system is that the crossover point for the bass driver is 150hz but it's rolled off from 75hz to blend with the mid range driver. Can I accomplish this with an active xo?Apparently the JBL's in these cabs produce bass flat to 23hz :/ Any help is appreciated. My understanding is the crossover used for this speaker system was a tweaked Bryston 10B customized for the cabinet (re: the bass roll off at 75hz with xo point of 150hz). I'd like to purchase a cheaper XO to get a sense if its worth purchasing a high quality XO. Thank you

Lee in Montreal
10-25-2014, 01:55 PM
Hmmm... For a 2235 to go flat down to 27hz, it must receive some serious processing, especially in such a small cabinet. I think the processing is not just a simple graphic equalization, but something that was popular with Kef in the 1980s. Check for "Kube". Basically it is a Linkwitz transform circuit... But beware of excursion. I had such a device and it was impressive.

What a Linkwitz transform circuit does
http://sound.westhost.com/linkwitz-transform.htm

http://sound.westhost.com/ltc-f4.gif

http://www.allegrosound.com/KEF_R107_fig-02.jpg