Crossover settings......whats this all about |
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DAVID_L_PERRY
Registered User Joined: 05 July 2006 Location: United Kingdom Status: Offline Points: 89 |
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Posted: 21 January 2007 at 8:32am |
Couple of questions:-
This has just come third hand to me so may be a case of chinese whispers... I have just been told that Linkz riley is more suited to the crossover of the top end (Low/mid/high) where as Butterworth is more suited to low freq crossovers....(I may have this the wrong way round) This same person also suggested that the low/mid crossover freq should overlap more but still use a 24db slope. This does not make sense to me. What he did was have his subs running to 80hz, and then lower mids set from 60-200hz..rather than 80-200 I thought the whole point was to seperate as much as possible the freq from each part of the system. Even if this is all nonsense I want to better try and understand the difference between Linkz Riley and Butterworth crossovers when setting up mine and other systems and also the preffered freq slopes. I tend to use 24db slopes. Any advice welcome Dave Always learning new tricks for the old dog |
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jethrocker
Old Croc Joined: 07 June 2006 Location: Chiapas, Mexico Status: Offline Points: 1942 |
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I think really it all depends on what cabs you're using on different ranges. If you're sub is lacking at the top end, or your upper bass at the low end, a flatter resaponse could be achieved by overlapped crossover points.. but I guess the exact figures would need working out after proper measurement of the rig and modelling of response with the "corrective eq" from the overlapped cross points.
Of course, oiverlapping cross points can just as well cause cancellations and a worse response overall.
As far as I know, Linkwitz Riley are the only topology that sum to a flat response-thats a flat electronic response and doesn't account for the response of the system. Butterworth tends to have a lump in response just above low cut off, and can therefore be useful to correct dips in system response, as can other slopes with their own peculiarities. I think the main differences in response of different slopes is the q of the filter...affected by the different component value ratios used to achieve the different topologies.
Oh, and Linkwitz Riley is a form of Butterworth, just two aligned butterworth sections in series.
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tb_mike
Old Croc Joined: 01 October 2004 Location: New Zealand Status: Offline Points: 2744 |
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theres no one perfect filter. Im sure their somewhere online.
Bessel,chebyschev,elliptic,butterworth,linkwitz riley. Infact linkwitz riley should be the easiest to find online. What your looking for is a flat summed response. So take into account your acoustic roll offs,add the electrical,to get your summed final response.(ie measure and fiddle) Phase is another issue,that will take some reading. www.geocities.com/kreskovs |
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Calitri
Registered User Joined: 02 November 2004 Location: Finland Status: Offline Points: 132 |
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And also you have to remember, that it's never about the electronic x-o point rather than acoustical x-o point. Like typically between bass and mid, where the bass might be around 6-10 dBs louder. So if you cross the bass from say 90 Hz with L-R 24dB/oct, you'd propably have to cross the mids from around 110-130 Hz with L-R 24dB/oct. So in the end your true acoustic x-o point would be around 105-110 Hz and that's the only thing that counts, not the electronic x-o point. Here's an example: We did a nice little techno party and the bass bins (4 18" reflex) were pumping from 32-95 Hz, mid bass (2 2x12" reflex) were used for 95-350 Hz and tops from there on. However the bass were crossed from 65 Hz with L-R 24dB/oct and still the response, even with some 90 Hz -4 dB EQs, pushed a flat response from 32-95 Hz, so in other words, the mid bass had to be crossed from where the bass acoustically rolled off. Hope that helped you a little bit.
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james folkes
Old Croc Joined: 08 January 2005 Location: United Kingdom Status: Offline Points: 3064 |
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calitri and mike, you have both helped me greatly here. whilst it's kind of stuff i already knew in concept, i feel i now have a methodology for attempting to turn the theory into practical effects. this is made so much simpler by modern digital crossovers! i [heart] my dcx 2496s... cheers guys!
james. |
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mardy hippy.
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