# crossover/filter questions



## hopkid929 (Jan 11, 2008)

Hello all,

I'm trying to understand crossover and filter application in 3-4ways systems and have a few questions.

1. I would like to use a 2nd order LR (linkwitz-riley) crossover for all 4 crossovers. The 2nd order LR results in a 180 deg phase change... thus in a two way system, one driver would be wired reverse polarity to have both drivers in phase. How will this work in a 4way system?

2. I will be using LCR, CR and L-type attenuation networks where applicable in this setup. Does it matter which order I use these components? I understand from a block diagram point of view that they must be after the crossover, but what about in relationship to each other?

3. Since I will be crossing over between two midrange drivers (high-mid/low-mid) less than 3 octaves apart, does anyone suggest using a different type of crossover than an LR to lessen the summation error? I read about 1st order Butterworth however I'm not sure the slope of the crossover will be enough.

Thats it for now, thanks in advance!


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## Anthony (Oct 5, 2006)

Hello, some quick answers for you (the ones I know anyway):

1. Just keep reversing phase. Sub +, Woof -, Mid +, Tweet - or vice versa.
2. The LCR and CR are usually impedance correction (Zobel) and are right off the driver. In fact, think of them as being part of the driver once they're installed. L-pads for the mid and tweeter are usually right before the driver as well. The whole point of a proper L-pad is that it does not change the impedance curve of the driver, so the crossover design is the same. I have never used an L-pad and Zobel in the same circuit so I have no idea how that would work.
3. I'm not sure how to answer this one. L-R crossovers sum flat in power response, so 2nd or 4th order should work just fine here. Maybe someone who has tried this double-mid setup can chime in and help.

Good luck.
Anthony


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## hopkid929 (Jan 11, 2008)

Thanks Anthony! I wasn't sure about the polarity switching in this setup.

If anyone has experience with a 4 way system, or a link to a detailed 4way crossover design I'd be interested.


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