• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Help with new PA speaker system setup

tbirdsp

tbirdsp

Sep 18, 2012
1,799
913
Chattanooga, TN
#1
I had been using a pair of powered Behringer B212D (12" + horn) tops with a single B1500D (15") powered sub. Got good results without too much trouble. Became tired of moving the 97 lb sub, so I recently upgraded my whole speaker system.

Board is a Mackie ProFX16. I'm using the built-in 7 band graphic eq for the mains.
Behringer CX2310 crossover with mono sub out.
[Invalid or Expired Link Removed]
Peavey IPR 1600 DSP
Crown XLS2000
A pair of Carvin LS1801 18" subs (8 ohms each)
A pair of Carvin PM12 top speakers (8 ohms each)

Setup: Running stereo tops with the IPR1600 into the PM12's. I have the XLS 2000 bridged mono into the pair of LS1801 subs for a 4 ohm load. Not using any of the DSP in the amps.
I have the crossover set for stereo 2-way, but I'm only using the "high" output of each side for the top speakers, since I'm using the mono sub output for the low end. Pretty much the only reason I'm using the crossover vs just the DSP in the amps is I want to run stereo, but wanted a summed mono sub output so I could bridge the XLS2000 amp into 4 ohms.

I have everything set up in my garage right now, running recorded (CD) music. I have it sounding OK, but had to use what I think are "weird" crossover settings. My intent was to just have to subs running 100 hz and below. Note the resolution on the freq knobs is pretty coarse.
Ended up with this, after messing around until it sounded decent to my ears:
Input gains: +2 db
X-over freq 60 hz
Low output: not used
High output: -2 db
Mono sub x-over freq: 145 hz
Sub level: +6 db (maxed out)

The amplifier volumes are all the way up. Nothing is clipping or anything. I have the EQ on the board set flat, as I'm trying to get a baseline for the crossover settings. I started out with the levels on the crossover at unity, but wasn't getting anywhere near enough low end.

Anyway - I guess I'm just rambling.

Given the gear I have listed above, how would you run it?
 
#4
I try to avoid 60hz crossover points as that is the meat of the kick. I would turn off the subs, turn down the xover point on the carvins to 0. Turn up the music and turn up the HP on the xover just till the bass loses its flabbiness and starts getting punchy. Then turn the subs on, again down to 0 but on the LP and bring it up just to where it fills in what is missing. Try not to look at the numbers on the knobs and let your ears do the work. When I was using Carvin PM12's as mains 100hz was a pretty good xover point.
Remember every room will change that point a little.
 
#5
I would set x over for top @ 100hz
And the subs the same. You said you had HP for tops at 60 and mono sum LF set at 145. So you basically will have a bump in system freq response from 60-145 as both tops and sub are getting those freq.

If not getting a balance you like between HF and LF. Turn down the HF out on x over a bit then turn up the master on the mixer a bit until you get what you like without the HF cutting your head off.

I play music thru my system and set input ch gain, them set fader at 0. Then bring master fader up to just before clipping/peak. Then turn amps up to clipping and back off a notch.

You can do this with your speakers unplugged to save your hearing and not stressing your speakers. Only takes a minute or so and won't hurt amps for a short duration. Once you make note of where amp inputs are at. Turn them down, turn mixer master down. And plug your speakers back in.

Now you know that your headroom on your amps and mixer are the same and you know you can run your mixer master up to just below peak and not be clipping your amps.

[Invalid or Expired Link Removed]
 
#6
Thanks for the replies guys.

First off - I'm really not thrilled with this Behringer crossover (surprise, right?:rolleyes: )
I read online in several places that the "crossover" freq setting on the mono sub out was actually just a low-pass filter - so all freqs get sent to the main channels of the unit. So one would assume that the channel freq adjustments would have no effect on the sub out - but that is not the case. Both the sub feq knob AND the channel freq knobs seem to affect the sub out.
I thought the freq settings I ended up with were weird too, but that was what sounded best to my ears.

Again - I am mainly just using the crossover to get a summed sub out so I can run the sub amp bridged mono but keep the tops stereo. In fact - when I first hooked everything up I set the XLS 2000 for a 100 hz low pass and the IPR 1600 for 100 hz high pass and just went a tad high/low on the crossover freq settings - basically just letting the amp DSP handle the crossover freqs. At that point (before I realized the difference in input sensitivity between the two amps) I thought something was screwy because I had to crank the sub output all the way up and reduce the high output to get a balanced sound.
Later on just for grins I set the crossover outputs (sub and high freq) to unity (I had set the mixer gains and the crossover input gains earlier), maxed out the XLS 2000 sub amp and turned the attenuators on the IPR1600 down - then slowly brought them up until I got a balanced sound. They ended up at -12.

I may just pick up another Crown XLS, either 1500 or 2000, so I'm working with amps with he same input sensitivity. I know, it's not a big deal as long as I can compensate with the amplifier gains, but it would make everything easier if they were the same. I can use the IPR1600 for monitors.
 
#8
Subs handle the extreme low end of the audio spectrum where the driver sensitivity is lower. My subs are rated at 800w, my tops/mids at 240. Efficiency specs are 94db and 98db respectively. 4db difference is my starting point and as said before the room could easily add/subtract at any frequency.

As you won't have a sound meter at thr gig, use use your ears not your eyes.
 
#10
The crossover is not that bad at all, but yes, you're right, the sub output is just a summed L&R with the top chopped off, which is all it really needs to be. However, the crossover is also splitting the main signal to HF and LF, so you need to make sure that your settings are correct.

The tops you are using have internal crossovers? I think so. So the crossover is not as straightforward to set up. The speakers want a full band signal, with just the bottom trimmed off - so you don't want to connect to the sub bass output at all on the crossover, you need to select the low/high setting and then put the split very low, as mentioned above, and feed the subs with that from the output. The summed sub output isn't useful at all. Have you tried this? I'm wondering if you are using the hi output to the Carvin speakers, and the sub output to the subs - which won't give you as clean a crossover, and the subs and the Carvin driver may be fighting against each other?
 
#11
It's common to have subs output higher than HF/MF.

My bi amp set up 2-215 subs, 2 115 w/horns. X over HF output is -5 to -6 db
LF output +6 to +8 depending on overall system volume. Most of the LF energy is just kick drum. LF is compressed and limited seperately from the H/M freq.
 
#12
I use 2 crown amps 1500-2500 in highpass/lowpass config weekly with my bar DJ/pa. The input from the board goes into the 2500 and then it is xlr looped to the 1500. The 2500 is for the subs ( 1x18 ), and the 1500 for the mains ( 2x15x1 ).
I also keep the attenuators on the amp for the mains down a little bit so it is more "balanced" sound.
 

Latest posts

Top Bottom
Back