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Author Topic: LAB on Rock concert  (Read 7122 times)

Bogdan Popescu

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LAB on Rock concert
« on: May 16, 2004, 04:45:32 am »

Hi,

This will be my first 5000+ people rock event with the LAB's. My setup will be much different from other concerts so i wanna check a few things with the LABsters here Very Happy

I will have on each side 2 LAB's, 3 double 15" (front-loaded K15LF), 4 x 3way boxes (K15LF+Beta8+PSD2002).
I know i might be a little short on top's. I am working on 2 top's frontloaded with 2xKappa Pro 10 and 1 PSD, which i will probably fly on the stage.
I power all LABs with 1600W/4ohm and will use 2 DCX2496 processors to align the whole system.
Loading all 4 LAB's in the middle is not possible.
I need any good suggestion, comments, how would you do it, is it enough ?

Approx 70m from the stage begins a park with a few tree's

I appreciate all your help
best regards, Bogdan
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Brad Litz

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Re: LAB on Rock concert
« Reply #1 on: May 16, 2004, 01:08:59 pm »

You need to group at least 4 together to get proper horn loading. Fewer and you'll lose the low bass they are famous for. Two together will work but you'll need to protect them with a high pass filter. People who have stacked eight together say the performance is fantastic.

The pro's here can tell you where to set the filter for two.
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Brad Litz

Bogdan Popescu

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Re: LAB on Rock concert
« Reply #2 on: May 16, 2004, 01:50:48 pm »

Hi Brad,

I know i would need min 4, but the budged does not allow that for now. I also know a few here use them 2 + 2 and did OK. I am thankful for every input on this.

From my experience, i did fine with filters set to 80Hz. I have 6x15" to cover up from 70-80Hz plus the 3x15" on the fullrange boxes. I am more worried about the mid-high...

Thank you,
Bogdan  Smile
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Tamas Tako

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Re: LAB on Rock concert
« Reply #3 on: May 17, 2004, 04:20:42 am »

Hi Bogdan,


I used this weekend on an open air event 2x4 LABs and have some opinions:

If I need even coverage, I have to center stack the 2x4 or maximaly 4m from each other and a little bit offstage dirrection.

Other solution is to put them as Left-Right stacks but 45 degrees offstage. This also gives quite good even coverage, but less SPL!
Therefore the solution would be 2x4 LABs 45 degrees offstage and 1x4 LABs in center. this gives enough power for open air rock for 50-60meter distance. (120dB max) and beside this an even coverage.

I think less than 2x 4 LABs open air is not good for rock and not good for any music material for an audience of 5000. 2x 2 is not enough. Maybe indoors, where room gains the low end, but not open air.

However I can understand your points regarding budget... Crying or Very Sad


cheers,

Tamas
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Bogdan Popescu

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Re: LAB on Rock concert
« Reply #4 on: May 17, 2004, 01:33:02 pm »

Hi Tamas,

Yeah, the budget is low  Crying or Very Sad Also the budget of the show, also my budget, but this is a reality of our region. To have an idea, on the same event last year they hired a "sound company" that promised 2x16kW and came with 2000W powered by a single amp of 1200W/channel, everything on the stage. So this year we will be SCIENCE FICTION.

We are so tight with our system, because we have to power up 2 separate stages, with different kind of music on this event.

Would it help to let the 15" woofers we have to go lower ?
There will be a total of 9 x 15" (K15LF) per side

Thanx,
Bogdan

PS: ...and in front of the stage there will be no more than 3000 people, the rest will hang arround near the place or on the second stage
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Phillip_Graham

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Re: LAB on Rock concert
« Reply #5 on: May 17, 2004, 04:54:18 pm »

Bogdan P. wrote on Sun, 16 May 2004 13:50

Hi Brad,

I know i would need min 4, but the budged does not allow that for now. I also know a few here use them 2 + 2 and did OK. I am thankful for every input on this.

From my experience, i did fine with filters set to 80Hz. I have 6x15" to cover up from 70-80Hz plus the 3x15" on the fullrange boxes. I am more worried about the mid-high...

Thank you,
Bogdan  Smile


Hey Bogdan,

The filter being referred to here is a High Pass, not a low pass.  You need to protect the 12's from ultra low frequencies, so you should set a high pass of at least 12dB/octave.

You have 6 dual 15" boxes, and 4 lab subs to work with.  I am with Tako, place all 4 lab subs in front of the center of the stage, and the dual 15's below the tops stage left and right.

If all 4 LABS are together in a line, they will couple at the lowest frequencies, giving you some additional extension.

I would have the dual 15's run down to around 45hz to give you some extra low end.

As for your tops, you can increase the throw by stacking them vertically. So rather than 4 wide, I would do 2x2 like this:

W       W
m       m
horn    horn
horn    horn
m       m
W       W

And then splay the tops along the coverage pattern of the horn.

So, in summary

Top Top                                              Top Top
Top Top                                              Top Top  
Sub Sub sub                                      Sub Sub Sub
---------------------------------------------------------  
                      LAB LAB LAB LAB
Guessed ranges:
Labs: 35-80hz
Subs: 45-100hz

It's really hard for me to say without me sitting in front of the PA with my smaart rig out.  I think you'll be OK as long as you are doing the mixing, and keep the volumes around 95dBA or so.

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Tamas Tako

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Re: LAB on Rock concert
« Reply #6 on: May 18, 2004, 03:50:09 am »

Hi Bogdan,

Yes I think that adding the 9 15" front loaded  speakers would help a lot, when they can play down to 45-50Hz.
I don't know if you have possibility to set delays electronicaly?
BTW, you have to delay the 15" woofers to the LABs mechanical or electronical when they work overlapping in frequency range.
I would use crossower for the LABs 30Hz... 80-90Hz 24dB/oct Linkwitz-rilley and for the 15" the same HPF (30Hz)
You will need to change the polarity of the LABs (-) to compensate the 80-90Hz phase shift of the crossower.

You can set delay the easyest way, when you reverse the polarity of the LABs again (+) and set the delay of the 15" woofers(and of course of the mid and high range too)until you have a massive big cancellation between the LABs and the 15" woofers in the 40-80Hz range. (you must find the broadest and biggest cancellation).
then you can reverse the polarity of your LABs again (-) and the summation will be perfect.

The location where you have to hear this is 20-30m away from the subs and on axis of one side of the subs (the 15" woofers must be placed as close to the LABs as possible)

I hope this will help a bit and you will have a great show with satisfied customers.


cheers,

Tamas
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Tom Herr

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Re: LAB on Rock concert
« Reply #7 on: May 18, 2004, 08:58:37 am »

I did a show last summer for a similar sized event. Using 4 labhorns, 2 per side. Had plenty of low end. Tops were EV, 2-12 X 2" horn. 3 per side, Material was rock-n-roll, several bands from SRV type stuff to Metalica cover material. Never saw a clip light all day. Levels were well over 95db.

Take your time and make sure your DSP settings are right. Keep an eye on your clip lights, and you should be fine. Is it ideal? no, but do-able.

Have fun.
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Tom Herr
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raj

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Re: LAB on Rock concert
« Reply #8 on: May 19, 2004, 01:42:59 am »

I like the arrangement you guys have recomended Mr Bogdan for his rig,Iike this he will get the best from all the speakers,
I would like to know if rest of the speakers will need a little deley to be at par with the lab subs ?
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RL

Tamas Tako

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Re: LAB on Rock concert
« Reply #9 on: May 19, 2004, 05:36:54 am »

Hi Tom,


I can belive that there was well over 95dB... Laughing  Embarassed
However Phil wrote 95dBA!!!!
I think in a rock concert 100-105dBA is sufficient ( this is equal to ca. 110-120 dB unweighted)

cheers,

Tamas
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