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Speaker placement...
Old 21st October 2013
  #1
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Speaker placement...

Ok so I'd like to use these two sets of speakers as FOH mains...I want one Peavey and one Behringer on each side so what are some placement options that combat phase cancellation? Each pair would be powered by the EP2500 below and I have two amps...
Also with the crossover below, can I use a Y adaptor coming out of the crossover and into each EP2500?

Peavey :: Impulse

Behringer B1520 Pro Eurolive Professional Series 15" 2-Way Speaker | Musician's Friend

Behringer: EUROPOWER EP2500

Behringer SUPER-X PRO CX2310 Crossover | Musician's Friend
Old 21st October 2013
  #2
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The Behringer and Peavey are both full range boxes so why do you want one of each per side? Is the system mono or 'stereo'? And what is the purpose of the crossover?

It doesn't sound like you're running a split system such as instruments in one speaker and vocals in the other nor have you indicated needing extremely wide coverage so unless I'm missing something I would just pick one speaker pair and use them.
Old 21st October 2013
  #3
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Running in mono and I want to use all four as mains but I don't want both Peaveys on one side and the Behringer on the other side...It wouldn't look right to me...So I want a Peavey and a Behringer together on each side...Can they simply be on stands next to each other? And they would be on each side of the stage, maybe 3 feet apart...I'll use the crossover on the 2 subs and 4 mains to hopefully clean it up...
Old 21st October 2013
  #4
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Quote:
Originally Posted by Know Peace View Post
Running in mono and I want to use all four as mains but I don't want both Peaveys on one side and the Behringer on the other side...It wouldn't look right to me...So I want a Peavey and a Behringer together on each side...Can they simply be on stands next to each other? And they would be on each side of the stage, maybe 3 feet apart...I'll use the crossover on the 2 subs and 4 mains to hopefully clean it up...
Why do you want two mains per side? Do you need more horizontal coverage than one nominal 90-100 degree box per side can provide? Might one of the speakers on each side be acting more as a front or side fill than as a main?

If you are doing this because you think having two speakers per side with them both covering the same listeners is going to provide significantly greater output then you might be surprised by how little difference on the overall level it actually makes along with incurring some negative issues such as combfiltering.
Old 21st October 2013
  #5
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Quote:
Originally Posted by museAV View Post
Why do you want two mains per side? Do you need more horizontal coverage than one nominal 90-100 degree box per side can provide? Might one of the speakers on each side be acting more as a front or side fill than as a main?

If you are doing this because you think having two speakers per side with them both covering the same listeners is going to provide significantly greater output then you might be surprised by how little difference on the overall level it actually makes along with incurring some negative issues such as combfiltering.
Combfiltering! Thats what I meant...And the reason I want the two per side is I want more overall power...Like having a pair of two 15 cabs per side...I have two EP2500's and 4 speakers and I want to use them...How can I set them up and avoid combfiltering?
Old 21st October 2013
  #6
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Quote:
Originally Posted by Know Peace View Post
Combfiltering! Thats what I meant...And the reason I want the two per side is I want more overall power...Like having a pair of two 15 cabs per side...I have two EP2500's and 4 speakers and I want to use them...How can I set them up and avoid combfiltering?

Doubling the number of cabinets will yield a minimal increase in "overall power". It will require more amplifier power input, but will yield only a few dB more SPL. And the destructive interference (comb filtering) you get will degrade the sound quality, negating any increase in overall level.

The proper way to get more "overall power" is to get more powerful speakers. If the ones you have now will give you a usable SPL of 130 dB, what you need is not two more of the same but two different cabinets capable of a usable SPL of 136 or more.

You're going to have to give up on trying to maximize the stuff you have and go for something proper. Combining like cabinets is problematic enough. Combining mis-matched boxes is a recipe for really bad sound.
Old 21st October 2013
  #7
KEL
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I'd say go ahead and throw them up on stands with horns as close to each other as possible and the cabinets splayed out a bit. Why not. The 1520 is a narrow horn, besides below Xover point that horn pattern goes out the window for the most part anyhow. Comb filtering can be of minimal impact sometimes anyhow, it's sometimes written like it is the end of the world.
Old 21st October 2013
  #8
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Dude... Just spend some time watching this guys videos and see if they help you.
Dave Rat - Live sound Subwoofer configurations Part 3 - YouTube
Old 21st October 2013
  #9
KEL
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Dave Rat is cool but none of his videos address this guy's question.
Old 21st October 2013
  #10
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Quote:
Originally Posted by KEL View Post
I'd say go ahead and throw them up on stands with horns as close to each other as possible and the cabinets splayed out a bit. Why not. The 1520 is a narrow horn, besides below Xover point that horn pattern goes out the window for the most part anyhow. Comb filtering can be of minimal impact sometimes anyhow, it's sometimes written like it is the end of the world.
Kel....

You can always try it, but the OP is looking for LOUDER. The 3dB increase in SPL is not going to be that noticeable. But the increase in reflected sound due to the wider dispersion from the splayed cabinets will increase the "mud level" of the sound in the room.

When I walk in to mix on a house system set up with 2/side like you suggest, the best fix is to turn off one pair of speakers. Clarity goes up, SPL does not decrease such that anyone would really notice.

You want loud, buy loud. Don't expect "not loud enough" x 2 to yield the desired result.
Old 21st October 2013
  #11
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Quote:
Originally Posted by KEL View Post
Dave Rat is cool but none of his videos address this guy's question.
I think maybe you need to watch them to as he addresses comb-filtering with subs. Maybe subs but its still the same principle.
Old 21st October 2013
  #12
KEL
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Quote:
Originally Posted by Wyllys View Post
Kel....

You can always try it, but the OP is looking for LOUDER. The 3dB increase in SPL is not going to be that noticeable. But the increase in reflected sound due to the wider dispersion from the splayed cabinets will increase the "mud level" of the sound in the room.

When I walk in to mix on a house system set up with 2/side like you suggest, the best fix is to turn off one pair of speakers. Clarity goes up, SPL does not decrease such that anyone would really notice.

You want loud, buy loud. Don't expect "not loud enough" x 2 to yield the desired result.
I agree. But, if the OP already has these cabinets and wants to go ahead, let him try it and learn. If this is something he's considering buying then by all means skip that idea. But, set them up, play some music, adjust the splay, walk the room and see where it falls off. If it doesnt work, unplug two of the cabinets. I didnt see any description of a room here. I doubt you or i would walk into a briefcase gig with this setup but I have run pairs of 15+ cabs before a zillion times and sometimes it works just fine.
Old 21st October 2013
  #13
KEL
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Quote:
Originally Posted by 24 I/O View Post
I think maybe you need to watch them to as he addresses comb-filtering with subs. Maybe subs but its still the same principle.
not quite. besides, most of what Dave is doing is forming a cardioid pattern, creating comb filtering, for specific frequency cancellation on stage.
Old 22nd October 2013
  #14
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So help me understand how by having an amp and two speakers and then adding another amp and two more speakers doesn't make the system louder...
Old 22nd October 2013
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Quote:
Originally Posted by Know Peace View Post
So help me understand how by having an amp and two speakers and then adding another amp and two more speakers doesn't make the system louder...
OK.

If you have a single speaker that can deliver 120 dB SPL long term and add a second, identical speaker, you increase your output by 3 dB. But that's not the whole picture.

Double the amount of sound delivered requires a 6 dB increase in SPL. BUT...to have an SPL that is perceived to be double, you actually need a 10 dB increase in SPL.

So a 3 dB increase can be regarded as minimal, not really enough to make much of a difference at all.

FURTHER, a single point source (one speaker) outputs relatively coherent sound. Add another speaker and the contructive/destructive interference (comb filtering) begins the degredation of the sound from maximum coherency downward.

So by adding a minimal amount of overall output by doubling the number of speakers, you have introduced factors that make the sound less coherent. Less coherent sound, while technically "louder", will lack clarity. So you're left with slightly louder "mud" for your investment in more speakers and amps. You've essentially spent your money to make the sound SLIGHTLY louder, but have sacrificed clarity and sonic integrity.

Put all this in a confined space (a room) and the increased dispersal of sound from the multiple cabinets increases the amount of reverberative sound. This also degrades the sound quality and clarity.

So this path to "louder" is in reality a path to "poorer".

It's just physics. There's no way around it but to stick with a minimum number of cabinets (two is the practical number, one/side) and use cabinets which each have a higher SPL capability.

Clearer than that I cannot make it.
Old 22nd October 2013
  #16
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Unfortunately it makes perfect sense...So the same will go using two at the front of the stage? Sorry, don't mean to beat this to death, just asking....So how is it done at big concerts where theres a dozen hanging from trusses on both sides of the stage?

So how about using one EP2500 per one Peavey Impulse per side?
Old 22nd October 2013
  #17
KEL
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Quote:
Originally Posted by Know Peace View Post
Unfortunately it makes perfect sense...So the same will go using two at the front of the stage? Sorry, don't mean to beat this to death, just asking....So how is it done at big concerts where theres a dozen hanging from trusses on both sides of the stage?

So how about using one EP2500 per one Peavey Impulse per side?
That's a whole different area, line arrays. And Don't put the cabinets on the front of the stage either.

Do you already own these 4 cabinets? Do you have stands for them? Set it up and try it. Put the cabinets side by side. You can aim the center two cabinets inward towards the dance floor, the two loudest(probably the peaveys) straight out. Play some music. Walk around and listen. It will be louder. You aren't ruining your sound. There will be areas of weird cloudy sound. They could be insignificant. You can parallel the cabinets together off each side of that power amp. The behringer horn is quite narrow at 50 sym. It might play just fine with the peaveys. People use two trap cabinets per side all the time. It's perfectly acceptable. Your problem is further complicated by having two different brands/models

If you are thinking of buying these extra cabinets then listen to Wyllys and skip that notion.

Are you a band, DJ? What mixer board do you have?
Old 22nd October 2013
  #18
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Quote:
Originally Posted by KEL View Post
Do you already own these 4 cabinets? Do you have stands for them? Set it up and try it. Put the cabinets side by side. You can aim the center two cabinets inward towards the dance floor, the two loudest(probably the peaveys) straight out. Play some music. Walk around and listen. It will be louder. You aren't ruining your sound. There will be areas of weird cloudy sound. They could be insignificant. You can parallel the cabinets together off each side of that power amp. The behringer horn is quite narrow at 50 sym. It might play just fine with the peaveys. People use two trap cabinets per side all the time. It's perfectly acceptable. Your problem is further complicated by having two different brands/models
Other than line arrays, which are a special case, people using multiple cabinets are typically addressing coverage and trying to have each cabinet cover a different listener area with minimal overlap in their coverages. That is different than trying to obtain greater output by having multiple cabinets overlap in coverage and cover the same area.

As was already noted, if both speakers are exactly the same level and response then you might expect an overall 3dB increase in the direct sound, which is generally considered a just readily noticeable difference in the perceived loudness. However, with two different speakers per side that likely have different levels and different responses the overall increase in the direct sound level will probably be less than that and may not be noticeable.

The Behringer's the nominal pattern is 50 degrees vertical by 100 degrees horizontal, which is actually rather wide rather than narrow. But then again, I doubt either of those speakers actually hold the nominal pattern that well and if the patterns of the two speakers do not match then you seem likely to get some listener areas that are covered by two speakers and other areas that may only be covered more by one so I'm not sure that is desired.

Go ahead and try it before the event. If you are thinking it will be twice as loud or a considerable increase in perceived loudness compared to just the louder of the two speakers you may be disappointed.
Old 22nd October 2013
  #19
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I do have, for foh the four speakers and two EP2500 amps plus one EP4000 and two Black Widow subs in sealed boxes...I run the subs together next to each other front and center of the stage on the floor...Any thoughts on sub placement?
I promote Christian/faith based concerts...I book tours of like 3 bands that come together with full production and then like our last concerts, I brought in 9 other more local bands and run their sound myself...We do it all for free...Had about 1000 folks and it was an outdoor gig...
Old 22nd October 2013
  #20
KEL
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Nicely said Muse

phase and comb filtering is something we have to contend with, even when running two mains. At some point the polar patterns from the two cabinets will collide in the venue anyhow. if the mains are close to each other it'll be one place, further pushes the combing somewhere else. But sure, what you don't want is to introduce additional issues. All I'm saying is try it, test it.
Old 22nd October 2013
  #21
KEL
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Quote:
Originally Posted by Know Peace View Post
I do have, for foh the four speakers and two EP2500 amps plus one EP4000 and two Black Widow subs in sealed boxes...I run the subs together next to each other front and center of the stage on the floor...Any thoughts on sub placement?
I promote Christian/faith based concerts...I book tours of like 3 bands that come together with full production and then like our last concerts, I brought in 9 other more local bands and run their sound myself...We do it all for free...Had about 1000 folks and it was an outdoor gig...
you ran that system on these gigs?

what mixer board? do you have unused Auxes, subgroups?

you have two power amps for tops?
Old 22nd October 2013
  #22
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Know Peace,

If you have a mixer with subgroup outs you can try to route the vocals into one speaker pair and the rest of the band into the other. Try where the vocals sound best.
You will not have any phase problems.

Peter
Old 22nd October 2013
  #23
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Quote:
Originally Posted by Know Peace View Post
Unfortunately it makes perfect sense...So the same will go using two at the front of the stage? Sorry, don't mean to beat this to death, just asking....So how is it done at big concerts where theres a dozen hanging from trusses on both sides of the stage?

So how about using one EP2500 per one Peavey Impulse per side?
KP..

Now that you understand why two pairs of mis-matched cabinets will not be the best idea, here's a work-around for you: Dual PA.

What this means is to set up your 4 cabinets in a 2/side configuration (making sure to stand mount them and get the horns at least 7' in the air), use one pair for the band and one pair for the vocals. I'd use the wider patterned cabinets for the vocals.

This will let you use the power and gear that you have more effectively while minimizing the destructive effects of multiple sources. You will have to feed each pair from a different group or sub-group, so the ability to use this technique depends on the routing and output capabilities of your mixer.

This will also require more GEQ's...one per mix.

Good luck.
Old 22nd October 2013
  #24
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Wyllys is a little slow but he explains it much better!
Old 22nd October 2013
  #25
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Quote:
Originally Posted by Peter Z View Post
Wyllys is a little slow but he explains it much better!
Yup. Your post hit the Forum while I was composing mine, so I didn't see it until now.

I must admit that your idea is very good........
Old 22nd October 2013
  #26
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Yea I'm thinking of trying 2 pair of cabs. In situations where it may not work well or be needed, I'll have an extra pair of PRX415 monitors.

One set of cabs for vocals, one set instruments.
Clarity might be improved and guessing you would gain a little more volume/headroom too by giving each amp/pair of cabs a little less to handle.

Plus using a mono system I could do some trickery with a drive rack and a bi amped system.

Nice thing is that you can overlap cross over points in the DR which you can't do on most crossovers.

So I set up a 3 way stereo preset.
Run instruments subgroup to full range in Left side, vocals subgroup into full range right input.

Set LF 40-100hz (instruments LF)
Set MF 150-16khz (vocals)
Set HF 100-20khz (instruments HF)

DR LF left out to subwoofer amp
DR MF Right out to amp for vocals
DR HF left out to amp for instruments

Then I have separate para EQ, comp and limiting on each band as well as feedback suppression on all 3 freq bands.

What do ya think?

This trick can be done as well to use the MF band to process your monitor mix in a bi amped mono system.
Old 22nd October 2013
  #27
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Now this is what I'm talkin' bout!!! Thank you those that have patients with me and others alike and the rest of you that don't, you can shove it...lol...Naw, not really...I appreciate everyones input...My problem is I don't have a place to really try things out until the day of a show...We just did Fields of Faith, out on a HS football field and everything that could keep me from setting things up did...I made it to town with all my stuff thats stored in a room at a church by 1pm with a start time of 7pm and ended up not being able to set up till 6pm and trying to help with other things...I plugged in the last drum mic at 6:57 fired up the band and mixed on the fly...It actually turned out pretty good although I could've do better...
Oh and my mixer is a Behringer XENYX 2442 FX and a Behringer SUPER-X PRO CX2310 Crossover...No EQ's yet...
Old 22nd October 2013
  #28
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Quote:
Originally Posted by Know Peace View Post
.No EQ's yet...
KP....

There's your problem right there...or at least a very large part of it.

Without any system EQ, your system is limited to the first frequency to feed back. Louder than that you cannot get, so you're probably not utilizing more than 60-70% of the volume of which your system is capable. You don't need more speakers, you just need to optimize what you have.

Send me an Email address via a Personal Message and I'll send you a PDF of how to use a GEQ to maximize your system potential. It is a simple, step-by-step process requiring no special ear training...simply the ability to follow instructions. I cannot attach PDF's to PM's, so it's necessary to use Email.

W
Old 23rd October 2013
  #29
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Quote:
Originally Posted by Wyllys View Post
KP....

There's your problem right there...or at least a very large part of it.

Without any system EQ, your system is limited to the first frequency to feed back. Louder than that you cannot get, so you're probably not utilizing more than 60-70% of the volume of which your system is capable. You don't need more speakers, you just need to optimize what you have.

Send me an Email address via a Personal Message and I'll send you a PDF of how to use a GEQ to maximize your system potential. It is a simple, step-by-step process requiring no special ear training...simply the ability to follow instructions. I cannot attach PDF's to PM's, so it's necessary to use Email.

W
I got the email...Thank you, its some good stuff...I brought in Andrew Ironside from Hillsong years ago and now I remember him doing the same thing or something very close to it...
So, can I run from my mixer, into my crossover and to 3 amps...one to the subs and the other two to the two set of speakers with one pair running just vocals and the other pair running instruments? I am planning on EQ's but I can't yet...
Old 23rd October 2013
  #30
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Quote:
Originally Posted by Know Peace View Post
I got the email...Thank you, its some good stuff...I brought in Andrew Ironside from Hillsong years ago and now I remember him doing the same thing or something very close to it...
So, can I run from my mixer, into my crossover and to 3 amps...one to the subs and the other two to the two set of speakers with one pair running just vocals and the other pair running instruments? I am planning on EQ's but I can't yet...
To run separate programs (vocal, instrumental) you need separate sends. You could run the band via the mains out and the vocals from one of the sub-groups. Assign the vocals to the sub-group only and the instruments to the mains only. So...two sends to the crossover, one from mains (or two if you must) and one from the sub-group out. For this you'll need a TRS > XLR pigtail.

You can run the vocals full range, but most of us use a high-pass filter (HPF) on all vocal mics. You won't need to run the vocal half of the PA through a crossover as long as you high-pass all vocal mics.

But you really need that GEQ for the system...
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