If you have time to check different filter characteristics ( Bessel, Butterworth, L-R ) for the same slope, please let me know if you can really hear differences in practice.
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Hello. I saw that wiki, and I believe the LR-4 is 2 cascading BW. THe LR-2 filter is less straight forward (it's mentioned that it's a scalley filter with a Q of .5)
Ayways, I have the miniDSP plugin as reference and they have the LR-2,LR-4, and LR-8 filters in there.
It seems like in APO when i do a LPQ or HPQ with Q=.5 I get similar results as the graph I see in MiniDSP plugin.
IE. -6DB @ F0 and -14db @ F0/2 or 2*F0. However, supposedly the LR-2 filter has a 12dB/octave slope.
and casading two BW (Q=~.707 or fixed Q in APO) does give you LR-4 which is 24db/octave slope.
Anywas, I think APO LPQ with a .5 is pretty close if not it's the right LR-2 slope curve.
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and also from this discussion:
"Returning to the Wiki page and looking at the Qs required for Butterworth filters from 1 to 5 you'll find:
1st order Butterworth: Q of .5 (real pole)
2nd order: Q of .707 (2nd order)
3rd order: Q of .5 and 2nd order with Q of 1 (real pole and 2nd order)
4th order: Q of .541 and Q of 1.31 (both 2nd order)
5th order: Q of .5, Q of .618 and Q of 1.618 (first is a real pole and other two are 2nd order)"
So yah...
Two Low/High-Pass with fixed Q in series from APO would indeed yield a 2nd order LR-2 curve!
Just becareful, doing both Low and High pass with LR-2 results in a 180 degree phase shift. So either one of the driver needs its polarity inverted.
Thanks!
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Hello, anyone knows how to apply a LowPass and HighPass Linkwitz-Riley Filter?
LR-2 12db/octave slope.
Has anyone figure out how to this with the IIR maybe?
Hi,
as Wikipedia, L-R Filter is a cascade of 2 Butterworth filters ( Q=0.707 ).
https://en.wikipedia.org/wiki/Linkwitz%E2%80%93Riley_filter
Should be easy with Eq Apo.
If you have time to check different filter characteristics ( Bessel, Butterworth, L-R ) for the same slope, please let me know if you can really hear differences in practice.
Hello. I saw that wiki, and I believe the LR-4 is 2 cascading BW. THe LR-2 filter is less straight forward (it's mentioned that it's a scalley filter with a Q of .5)
Ayways, I have the miniDSP plugin as reference and they have the LR-2,LR-4, and LR-8 filters in there.
It seems like in APO when i do a LPQ or HPQ with Q=.5 I get similar results as the graph I see in MiniDSP plugin.
IE. -6DB @ F0 and -14db @ F0/2 or 2*F0. However, supposedly the LR-2 filter has a 12dB/octave slope.
and casading two BW (Q=~.707 or fixed Q in APO) does give you LR-4 which is 24db/octave slope.
Anywas, I think APO LPQ with a .5 is pretty close if not it's the right LR-2 slope curve.
My correction. With further research it seems like you are correct!
Refrence: http://www.tonmeister.ca/wordpress/2012/12/31/its-impossible-to-build-a-good-loudspeaker-part-1-crossovers/
Linkwitz-Riley 2nd Order
"A second possible crossover strategy is to use a 2nd-order Linkwitz Riley. This is similar to a 4th-order, except that instead of putting two 12 dB/octave Butterworth filters in series to make each section, you put two 6 dB/octave Butterworth filters in series."
and also from this discussion:
"Returning to the Wiki page and looking at the Qs required for Butterworth filters from 1 to 5 you'll find:
1st order Butterworth: Q of .5 (real pole)
2nd order: Q of .707 (2nd order)
3rd order: Q of .5 and 2nd order with Q of 1 (real pole and 2nd order)
4th order: Q of .541 and Q of 1.31 (both 2nd order)
5th order: Q of .5, Q of .618 and Q of 1.618 (first is a real pole and other two are 2nd order)"
So yah...
Two Low/High-Pass with fixed Q in series from APO would indeed yield a 2nd order LR-2 curve!
Just becareful, doing both Low and High pass with LR-2 results in a 180 degree phase shift. So either one of the driver needs its polarity inverted.
Thanks!