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Where do you set your PA crossover

smogg

smogg

Mar 27, 2007
5,365
6,189
NPR, Florida
Disclosures
I'm not crazy, I'm just a little unwell
#1
My drummer and I have come to a small disagreement with one of our guitarists. We currently use a pair of passive EV subs in our PA. They have a built in passive crossover (or low pass filter not sure what the correct phrasing is) set from the factory at 120 Hz. They are non adjustable. It seems to work fine as is for our needs.

The one guitarist wants to use his active crossover, says it will sound better. But, he wants to set it at 220 Hz. That seems a bit high to me and I feel would put too much low mid bass in the subs and get muddy real fast.

We are a rock band playing small to medium sized rooms. Is there a norm or rule of thumb for setting crossovers?

Thanks in advance for your recommendations.
 
#5
If the crossover is non-adjustable using another crossover on the sub won't have any impact unless it's below the factory crossover point.

It might help cut some high frequencies from the sub if the active has a high enough roll off.

You shouldn't set a sub that high unless your mains are seriously lacking in midbass and low mids.
 
#6
Our mains are A-OK. They are JBL 115's and handle low mid and mid mid just fine imo. I'll just let him know that the active unit will be redundant for these subs.
Thanks

afiaowo said:
If the crossover is non-adjustable using another crossover on the sub won't have any impact unless it's below the factory crossover point.

It might help cut some high frequencies from the sub if the active has a high enough roll off.

You shouldn't set a sub that high unless your mains are seriously lacking in midbass and low mids.
Click to expand...
 
#7
If there is an internal xover set at 120, the active xover will be doing nothing but adding a steeper slope to that 120. That may not be a bad thing, especially if your mains aren't crossed over... And that leads me to this question. Your mains are crossed over correct? If not your guitarist may be right about it sounding better, poor xover point selection though. If your mains aren't crossed over, try the active and start by setting at 120, this will give you a steeper crossover slope on the high side of the sub. It may actually squeak out a tiny bit more headroom out of the sub amp also.
Edit; my PA is crossed over at 100hz generally
 
#8
Trying to get sub drivers to also zip around an octave higher than they were designed for is just as bad as giving them too much content and/or power below their range, if not worse. Usually worse. They don't like it one bit.
Crappy sound followed by shopping for replacements.

Your guitarist just wants more of his instrument in the subs, to the detriment of the band's sound and finances.
Don't listen to him.

I'm around 90hz these days.
Depends on both cabs and the slope of the crossover and how much power to each.
 
#9
If I understand this set up correctly, the passive crossover applies to the subs only. I'm pretty sure the mains are running full range.


gearhead1972 said:
If there is an internal xover set at 120, the active xover will be doing nothing but adding a steeper slope to that 120. That may not be a bad thing, especially if your mains aren't crossed over... And that leads me to this question. Your mains are crossed over correct? If not your guitarist may be right about it sounding better, poor xover point selection though. If your mains aren't crossed over, try the active and start by setting at 120, this will give you a steeper crossover slope on the high side of the sub. It may actually squeak out a tiny bit more headroom out of the sub amp also.
Edit; my PA is crossed over at 100hz generally
Click to expand...
 
#10
This is of great concern to the drummer and I.
A) don/t need/want guitar(s) in the subs.
B) don't want/need low mid bass in the subs.
C) definitely don't want blown subs.

Problem is he insists he knows how to mix & run sound. But as soon as he said subs crossed at 220 red flags started flying. I'm just hoping we can talk some sense into him before he fries something.

KeithAlanK said:
Trying to get sub drivers to also zip around an octave higher than they were designed for is just as bad as giving them too much content and/or power below their range, if not worse. Usually worse. They don't like it one bit.
Crappy sound followed by shopping for replacements.

Your guitarist just wants more of his instrument in the subs, to the detriment of the band's sound and finances.
Don't listen to him.

I'm around 90hz these days.
Depends on both cabs and the slope of the crossover and how much power to each.
Click to expand...
 
#12
DWBass said:
:rollno: Send him here to explain his process and let the 'wolves' have at him! We'll learn him!
Click to expand...

LMAO; I just spit coffee all over my keyboard thank you very much. :D
I really would hate to have to do that to him (send him here) as I genuinely like the guy. But I'm holding this thread as a trump card so to speak if it turns out he fails to be reasonable. ;) Guess it's a wait see thing at this point.
 
#14
Does this dude have any money? If so, hold a deposit to replace everything and let him have at it and prove himself wrong. Some people don't learn without screwing stuff up for themselves.

Is it true this passive doesn't also filter lows out of the tops? If so, an active would clean up your sound quite a bit. Again, 80-120hz on the crossover.
 
#16
will33 said:
Does this dude have any money? If so, hold a deposit to replace everything and let him have at it and prove himself wrong. Some people don't learn without screwing stuff up for themselves.
Click to expand...
Ya he has cash flow but, these model EV subs are out of production. If they get blown repair/replacement would be a real PIA :(

Is it true this passive doesn't also filter lows out of the tops? If so, an active would clean up your sound quite a bit. Again, 80-120hz on the crossover.
Click to expand...
I'm pretty sure, I'll see if I can find any dox on them. maybe EV archives? These are the model that looked like a "Borg Cube" loaded with 2X15. One fires up and the other fires down. Nice and compact but not light. I'm all for sounding better if he will cooperate. ;)

Edit: found the pdf for the subs and this was one of the bullet points;
Integral passive-crossover filter
combined with unique acoustic
design allows for parallel operation
with full-range systems for
added bass response
Another part of the doc says (i'm paraphrasing here) to be careful with the amount of power pushed when the sub is run in parallel with a main as the only time they will share power in below 125 Hz (when using the passive X-over in the sub)

Here is link to the PDF:Invalid Link Removed
It really reads to me like the X-over only effects the sub. Maybe I'm misunderstanding the wording though.
 
#19
just a suggestion and apologies if this is a little off topic:

what are you using for a mixer? If you have a spare aux send (I prefer post fader, but a pre send will work ok), you could use it as a send to the active crossover, set a crossover point of 100hz and feed this to the subs. Send the mains L/R outs to the full range PA cabinets bypassing the active crossover). The key is to only feed the Aux send (which feeds the subs) with instruments that actually have sub frequency content in it.

There are only a few instruments that truly benefit from subs: bass guitar, kick drum, low tuned floor toms, keyboard synths/samplers/etc. (though you have to be careful as keyboard sub frequencies are notorius for mixing in with bass guitar and creating a mess, so be careful here.). Most of the instruments and all of the vocal mics dont NEED to be sent to the subs...there's nothing there for them.

The thing I like about this is that, since you wouldn't feed vocal mics, some of the drum mics, and guitar mics thru the subwoofer feed, you're reducing problems associated with stage rumble and necessary high pass filtering that you would NORMALLY need to engage to keep these frequencies (from the mics) OUT OF the subwoofer. IMO this is more focused and efficient way to maximize subwoofer output. Again, you'd only be feeding a few instruments into the subs, so it's much easier to manage. I'd also recommend you add a comp/limiter to the subs specifically, properly set so that you get the maximum BEEF without harming the amps or speakers.

IIRC, some mixers actually have a dedicated mono SUB output, that is assignable on a channel by channel basis. A similar routing could also be accomplished using a Subgroup feed on a mixer (if you have 4 or more subgroups available).

Anyhoo, just thought I'd throw it out there as it is a trick that I've had pretty good luck with on some systems. As you were...
 
#20
I've been running sound on small to ridiculously huge systems for over 20 years, and kick drum and break music are the only constants when it comes to subs.
Bass, keys and floor tom get into the subs less than 50% of the time in the real world.

Run your subs according to their published specs re: x-over freq and power. Do not allow anyone to influence you into deviations or you'll be sorry.
 

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