Difference between Linkwitz Riley and Butterworth Crossover? - AVS Forum
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post #1 of 12 Old 08-13-2014, 08:17 AM - Thread Starter
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Difference between Linkwitz Riley and Butterworth Crossover?

I've been playing around with my miniDSP and trying to decide if I want to attempt my own DIY project with active crossovers.

I've always seen these terms, but I don't specifically know what they mean or what the difference is. Anyone care to give me a quick explanation 101 on the differences between Linkwitz Riley, Bessel, and a Butterworth crossover ?

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post #2 of 12 Old 08-13-2014, 08:25 AM
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Read this:
http://www.bcae1.com/xoorder.htm
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Bill Fitzmaurice Loudspeaker Design

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post #3 of 12 Old 08-13-2014, 08:29 AM
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Butterworth for odd filters, Linkwitz for even. A Linkwitz is just cascaded butterworth filters. Bessel filters are for keeping an even phase/group delay.

Each of the filters has a different Q value, which give different amplitude responses. BW is Q or 0.49, LR is 0.71 (which is 0.49^2), which is because it's just a double BW filter.

LR filters are -6 dB at crossover, so they sum to flat (0 dB). BW are -3 dB, so they sum to +3 dB.

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post #4 of 12 Old 08-13-2014, 11:12 AM
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Great link. Thank you Bill.
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post #5 of 12 Old 08-13-2014, 11:17 AM - Thread Starter
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so if I wanted to cross over say (2) 15" woofers to (2) 6" midranges and then to a single CD/SEOS horn I would theorectically use a 3 way Linkwitz ?

Or is this something I'd play with and measure ?

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post #6 of 12 Old 08-13-2014, 11:27 AM
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Yes, you'd need to measure. But in general you would do a low pass on the 15", say 300 hz, a high pass on the mids at 300 hz, a low pass on the mids at say 1300 hz, and a high pass on the tweeter at 1300 hz. A 2nd order Linkwitz would be a good place to start. What SEOS/CD though? You probably don't need mids if your CD and waveguide can go down to 600 hz around, and if your woofers can go up to 1000 hz around.

You're doing active right?
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post #7 of 12 Old 08-13-2014, 11:41 AM - Thread Starter
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Yes active.

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post #8 of 12 Old 08-13-2014, 11:48 AM
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The filter you program into the mini actually has nothing to do with the XO you're trying to achieve. You might use a BW1 to get an acoustic LR6 if the driver has a natural steep slope on it. You also might put the filter at 700hz to achieve a 500hz XO. You also need to consider many more things.

Can I suggest starting with something much simpler. Active is not really any different than passive. You need to follow the same process.
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post #9 of 12 Old 08-13-2014, 12:00 PM - Thread Starter
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Well my first project is going to be a 2 way crossing a single woofer to a single CD.

Then I think I'll buy a cheap mid and try adding that.

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post #10 of 12 Old 08-13-2014, 04:07 PM
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Well that's certainly a much better way to start. Smaller and simpler is even better. Learning anything is about baby steps. Maybe start with a dome and paper 5.25" woofer. Compression drivers aren't easy to tame.
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post #11 of 12 Old 08-14-2014, 04:18 AM
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Quote:
Originally Posted by Mfusick View Post
Well my first project is going to be a 2 way crossing a single woofer to a single CD.

Then I think I'll buy a cheap mid and try adding that.

I am getting ready to dive into active speaker building myself. I already have my speaker parts. Just waiting until I can afford the wood, wire, speakon connectors and another iNuke1000dsp, which is what I am using as the active crossover devise, and it also has the benefits of being an amplifier too!
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post #12 of 12 Old 08-18-2014, 05:16 AM - Thread Starter
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I've always seen the iNUKES used for subs but never saw anyone comment on their sound quality for full range.

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