How to build DIY 8th order 48db active crossover??

Hybrid fourdoor · 27th October 2005, 12:39 PM

Sorry about the long title...wanted to make it as search friendly as possible...especially since Yahoo! crawls this place.

Couldn't really find any information on it, but do you build an 8th order active crossover by cascading two 4th order Linkwitz crossovers?

richie00boy · 27th October 2005, 12:56 PM

Linkwitz-Riley is just a filter slope characteristic. To make an 8th-order filter you just cascade 2 4th-order filters. The resulting Q will be filter_1 Q * filter_2 Q

If you want an 8th-order Linkwitz-Riley response, you need to cascade 2 4th-order Butterworth filters.

Jim85IROC · 27th October 2005, 01:24 PM

I'd suggest doing a little research on Jon Marsh's Cauer Eliptical filters on the DIY portion of www.htguide.com. His filters typically exhibit 8th order LR slopes with less components.

Emiel · 27th October 2005, 01:36 PM

Elliott describes the construction of a 36dB/octave filter (only the high pass section) cascading two 18dB/octave Butterworth filters. See http://sound.westhost.com/project99.htm, maybe some interesting info there!

Kind regards, Emiel

Hybrid fourdoor · 28th October 2005, 01:28 AM

I couldn't find the Project 99.

I found these active crossover filter circuit schematics. They cover;

Quote:

Butterworth 1st order Lowpass
Butterworth 1st order Highpass
Butterworth 2nd order Lowpass
Butterworth 2nd order Highpass
Butterworth 3rd order Lowpass
Butterworth 3rd order Highpass
Butterworth 4th order Lowpass
Butterworth 4th order Highpass
Bessel 2nd order Lowpass
Bessel 2nd order Highpass
Bessel 3rd order Lowpass
Bessel 3rd order Highpass
Bessel 4th order Lowpass
Bessel 4th order Highpass
Linkwitz 4th order Lowpass
Linkwitz 4th order Highpass

jdybnis · 28th October 2005, 03:40 AM

Look here: http://sound.westhost.com/articles/ntm-xover.htm

Also, if you want to go passive look at Jon Marsh's cauer elliptical crossover. Search for "cauer" on htguide.com. I like the transfer function better than the ESP crossover above. OTOH, implementing an active version is evidently challenging. You'll see something about that on htguide.

Emiel · 28th October 2005, 07:59 AM

Quote:

Originally posted by Hybrid fourdoor
I couldn't find the Project 99.

Sorry, here's the correct link:
http://sound.westhost.com/project99.htm

Kind regards, Emiel

27th October 2005, 12:39 PM	#1
Hybrid fourdoor diyAudio Member Join Date: May 2003 Location: Ft. Worth, TX	How to build DIY 8th order 48db active crossover?? Sorry about the long title...wanted to make it as search friendly as possible...especially since Yahoo! crawls this place. Couldn't really find any information on it, but do you build an 8th order active crossover by cascading two 4th order Linkwitz crossovers? __________________ I enjoy my organic shapes.....

27th October 2005, 12:56 PM	#2
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	Linkwitz-Riley is just a filter slope characteristic. To make an 8th-order filter you just cascade 2 4th-order filters. The resulting Q will be filter_1 Q * filter_2 Q If you want an 8th-order Linkwitz-Riley response, you need to cascade 2 4th-order Butterworth filters. __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

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27th October 2005, 01:24 PM	#3
Jim85IROC diyAudio Member Join Date: Dec 2003 Location: Stamford VT	I'd suggest doing a little research on Jon Marsh's Cauer Eliptical filters on the DIY portion of www.htguide.com. His filters typically exhibit 8th order LR slopes with less components.

27th October 2005, 01:36 PM	#4
Emiel diyAudio Member Join Date: Sep 2003 Location: Somewhere near Enschede	Elliott describes the construction of a 36dB/octave filter (only the high pass section) cascading two 18dB/octave Butterworth filters. See http://sound.westhost.com/project99.htm, maybe some interesting info there! Kind regards, Emiel

28th October 2005, 03:40 AM	#6
jdybnis diyAudio Member Join Date: Jul 2004 Location: Pasadena, CA	Look here: http://sound.westhost.com/articles/ntm-xover.htm Also, if you want to go passive look at Jon Marsh's cauer elliptical crossover. Search for "cauer" on htguide.com. I like the transfer function better than the ESP crossover above. OTOH, implementing an active version is evidently challenging. You'll see something about that on htguide.

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