Crossover slopes?

D

DrJones

New member
This is the first time i've had to set crossovers so i'm not sure if I have set them right. I have not pulled the speakers out of the cabs so I dont know the model but (4)JBL 15" subs and (4)EV 12" (2)Mid 24" horns Unknown (but I am sure of nice quality). 3 Seprate QSC amps (Mono) for Sub-Mid-Hi (another for Mon. But does not apply to this question). I do understand gain structure and unity gain. I setup everything even the new crossover. My question is what freq. do you start crossing over lows to mids and mids to highs? Where are they supposed to intersect? It sounds really good by my ears. I may have guessed right. Is there a basic rule to start with? I know rooms are different but there has to be a common start point. I am using a DBX DriveRack. Hope this helps.


Thanks
 
a lot of it depends on the characteristics of the speakers you're using. you would want to see a graph showing you the response accross a certain frequency range. it also depends on the slope of your crossover. you choose the crossover freq based on these things.

you want to be really careful that you don't cross too low on mid or a high!
 
looking at your graphs; ultimately you want to cross your components where the freq response starts to roll-off, provided the other pieces can handle those frequencies. you want to find a happy medium between all components. don't overload any one piece, spread the load out. lower frequencies chew up more of the overall power, so crossing them down from a high to a mid driver, or a mid to a sub will give you more juice. but at the same time you'll be removing some of the potential from you sub.
 
xistenz said:
a lot of it depends on the characteristics of the speakers you're using. you would want to see a graph showing you the response accross a certain frequency range. it also depends on the slope of your crossover. you choose the crossover freq based on these things.

you want to be really careful that you don't cross too low on mid-range speaker!
Click to expand...


OK!? Old Club with nice equiptment. I just replaced most of the equiptment besides the speakers. I like the EV & JBL, They are top of the line 20 yrs ago. The person who set this up is a jackass. I dont want to be that guy. So your saying I need the specs\on the speakers to properly set this up? Right now the crossover is set about lo starts a (20 hz ends at 160hz) mids start (125 hz ends at 8khz intersecting at about 140 hz @ -3db slope). highs start (7khz ends 20khz intersecting at about 7.5 k @-3db slope) This is FYI
 
without knowing the specs on the drivers you are using you can't make a proper decision. the big thing you need to be sure of is that you're not pushing any of the drivers too hard where they aren't capable of going. power-handling drops off in the lower frequencies, and you need to make sure you aren't driving any of the speakers too hard. otherwise you will max out the excursion and destroy them.

you should really try to figure out what the frequency responses of your individual units are. that way you know exactly what your speakers can handle.
 
Assuming that the highs are horn loaded, and not some JBL super tweeter design.... Try starting with the subs from 35- 106, the mids from 110 - 1.6, and the horns from 1.6 all the way out. The actual drivers may end up dictating things differently, but without knowing what they are exactly and what they are rated at, I can't give any better advice. I would also reccomend using a Lenkwitz-Riley 24 db slope between the crossover points. The most important frequency point in the setup I just mentioned is the frequency between the mids and the highs. If 1.6 is too low for your horns, you will have some issues and are putting the horns in danger. If however it is a 2" compression driver (fairly standard) 1.6khz or 1.8 khz should be a good starting point. If it is a 1.4" driver, you may want to raise that to 2.4khz or something similar.
 
$ .02

ok... so its old ev of "better" uality? well then its probably got an evl in it they were good "in general" down to around 50hz in alot of cabinetts but they are happiest at 100+ and top out around 4k (ymmv) as to the horn if its in a cab with the woofer they like to use a 1" throat for alot of that... usually with the 1824m which if push comes to shove will try to hit 500 hz but will bitch about it at break.... i used to have a live rig for my keyboards out of these two along with their st350 tweeter (passively crosse from 1824 dont remember the freq) and instead of your jbl's i used evs 15l in a tl style cab.... the crossover ponts i used were 80-1.2k try those as a start and experiment.... and ya shoulda heard that rig in stereo...... (smiles....picks up the bong)
 
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