State Variable Filter

[kipman725]

Hi I have been experimenting with active crossovers for my new line array open baffles, ribbon tweeters and subs. I notice that linkwitz seems to be using salen-key topology filters as is every other active filter used for crossover I have seen:
http://www.linkwitzlab.com/filters.htm#3
however the state variable filter seems to be supirior as it outputs LP and HP functions at the same center frequancy so mismatch between the LP and HP filters is eliminated.

I have attached a simulation of a 4th order State variable 4Khz crossover that has pi phase shift added to the lowpass output to allow both drivers to be in phase. It was designed using analogs filter tool:
http://www.analog.com/en/design-tool...urces/fca.html

According to Wikipedia the group delay is several orders of magnitude below the threshold of audiability:
http://en.wikipedia.org/wiki/Group_delay

[richie00boy]

Depending on the Q of the response, you don't always want the resonance frequency to be the same for each filter.

I also don't think that filters not exactly matching is a big problem, there's other - bigger - influences.