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10-07-2003, 09:39 PM
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#1 of 13 
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Member
Join Date: Sep 2003
Local Time: 07:46 PM
Local Date: 11-18-2008
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Butterworth, Linkwitz, Chebyshev, 2nd 3rd 4th order etc....what???
can someone please point me in the direction of a website that will explain all this stuff to me and what the differences are.
Its all so bloody confusing.
Thank you
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10-07-2003, 10:27 PM
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#2 of 13
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Member
Location: San Jose, Ca.
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Are you designing your own speakers?
Basic overview of Linkwitz-Riley and Butterworth:
http://www.trueaudio.com/st_xov_1.htm
Excellent book to pick up is the Loudspeaker Design Cookbook.
"The trouble with the world is not that people know too little, but that they know so many things that ain't so." - Mark Twain
HT: Marantz SR-8300, MA500 monoblocks x 2, 5X GR Research A/V-2s, Adire Audio Tempest sub, Denon 2900, Oppo 980H, Toshiba HD-A2, RC2000MkII remote, Panamax 5100, Panamax Max2 sub, Slim PS2, PS3 60G + 320G USB
Bedroom: Marantz PM-7200 Integrated, GR Research A/V-1s, Sony 222ES SACD, RC3200 remote, Panamax M8EX
Audio: Audioquest * Video: Bluejeans
My DVDs  My HT
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10-07-2003, 10:31 PM
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#3 of 13
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Member
Join Date: Sep 2003
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not designing my own speakers, just trying to better understand how things work.
but i barely understand a word that page is talking about.
I was looking for something more along the lines of definitions of each type sort of thing.
But i will read that page over a couple of times.
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10-07-2003, 11:36 PM
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#4 of 13
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Neil Joseph
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This belongs it the DIY/Advanced area.
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10-08-2003, 01:31 PM
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#5 of 13
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Member
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All those are the last names of people that have invented different types of crossover designs.
The 'orders' are how fast the XO (crossovers) stops the frequencies so
1st order = 6db/octave of roll-off
2nd order =12dB/octave of roll-off
3rd order =18dB/octave of roll-off
Roll-off means that the frequencies are decreased by the filter at the roll-off rate. So a 1st order XO centered @100Hz means that the frequencies will be 6db lower at 50Hz, 12dB lower at 25Hz and so on.
This is really only important to know if you plan on designing your own speakers.
For something like a subwoofer the best XO is 4th order (24dB/octave) Linkwitz-Riley
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10-08-2003, 01:54 PM
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#6 of 13
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Member
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ThomasW,
Quote:
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For something like a subwoofer the best XO is 4th order (24dB/octave) Linkwitz-Riley
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Understanding that the steepness of the slope (24dB/octave) rolls off the output of the sub at higher frequencies, is a symmetrical 4th order L-R for the sub & mains (an octave above the mains -3dB low frequency) an optimum solution for a complete XO between mains and sub?
Since my mains don't follow the THX standard, they don't have an acoustic rolloff of 12dB/octave @80Hz to add to the HT processor's 12dB/octave electrical rolloff @80Hz. |
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10-08-2003, 02:33 PM
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#7 of 13
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Member
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Bruce
Yes, IMO symetrical 24dB/octave is optimal for the sub/main XO. To obtain this I use the Marchand XM9 active XO's, not the sub out in my pre/pro
The nice about using 24dB L/R for the sub/main XO, is that it keeps the phase correct, and provides a steep roll-off slope. This helps prevent smearing of the stereo image with HFE 'leakage' into the sub, and prevents the mains from working to low.
I don't bother with any so called 'standards' (ie THX), my recommendations/experience is based on 3 decades of building and using subs
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10-08-2003, 04:19 PM
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#8 of 13
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Member
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So why should i use a 4th order linkwitz instead of a 4th order chebyshev or butterworth?? whats the difference?
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10-08-2003, 04:19 PM
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#9 of 13
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Member
Join Date: Jun 2003
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he gads, that make you... lets see... OLDER THAN 
I was thinking about building this Butterworth subsonic filter. What do you think about the DIY filter as opposed to spending a bit more and buy (a VERY hard to find) 24dB/octave Linkwitz-Riley. Do you have any suggestions for a good subsonic filter around 15hz at the -3dB point? All kidding aside, I always respect old-timers and their wealth of knowledge and wisdom  (I hope my inability to keep jokes to myself doesn't come back to burn me) |
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10-08-2003, 04:30 PM
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#10 of 13
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Administrator
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Quote:
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So why should i use a 4th order linkwitz instead of a 4th order chebyshev or butterworth?? whats the difference?
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Because if you sum that with the same symmetrical filter from the high pass side, the result is a flat response, and usually in phase. If you use the other types of filters, you'll get a bump in the crossover region, and your phase isn't as coherent.
If you have a Barnes & Noble bookstore (or Borders), I urge to you to try and find Vance Dickason's "The Loudspeaker Design Cookbook" and just leaf through it. It covers a lot of ideas about speaker design, and provides graphs and drawings of what we are describing.
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