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Using DBXPA for Multiple Amps and Monitors

shallom4usashallom4usa Posts: 26
edited May 2010 in Connectivity
I'm in the process of upgrading my PA system for bigger events. I'm on a tight budget but managed to purchased the following:
8 Peavey PV-215 for tops
8 Peavey PV-118 Subwoofer
Peavey FX32 Mixer
4 JBL EON15 - for monitors (these are all I have b4)
1 Driverack PA
4 Behriger EP4000 Watts Amp
And of course other stuff like mics.....

Question. How do I send signal into four 4000Watt Amps and 4 JBL Monitors from the mixer/Driverack at the same time? The Driverack can only send signal into 2 amps (High and Low) at a time. I am not using the mid at all, 8,000Watts for tops, 8,000Watts for Subs and the monitors.

Ouestion 2. What is the best way to arrange these speakers for huge outdoors concert?


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    GadgetGadget Posts: 4,915
    Boy your not going to like my answers... :roll:

    you will need to run 2 ohm stereo on the tops and 4 ohms stereo on the subs...

    The tops are 90x40 meaning that you have 360 degree coverage on each side of the stage.. I'm guessing you don't want to do that and if you overlap horn patterns all sorts of sonic chaos will degrade the signal for the people...

    Uli likes to copy things.. he copied the QSC RMX series amps.. one other thing that you might not want to hear is that the EP 400 is the exact same amp as the EP2500 with higher distortion figures...same amp.. a ripoff in my opinion...

    IF ... you want to run all that and monitor off the driverack.. :( you need to read this post...
    feeding 4 inputs from 1 output will likely cause you to have impedance issues...

    forget the monitors, set up a 2x6 set the mid and hi outs the same, set the HPF to 118hz LR24 (even if you believe that you have 2000 watts x2 @ 2 ohms that's still under 500 watts per cab, or 250 watts per woofer.. NOT a lot!) Set the LPF @ 118hzLR24 like the tops...put all the subs together in a block probably center clustered...

    on the subs... set the HPF to 50hz BW18 and set the switches on the 2 sub amps to "parallel" inputs...one sub amp per channel and one output from the driverack to the #1 input of each amp. you will only have 350 watts per sub as well... :| that's not much...

    put 2 tops per side with the woofers down and splayed to cover 90 on either side (NOT overlapping the patterns) and flip the other 2 upside down so the horns mate... same on the other side..

    Sorry, you really don't have "big concert gear" Good luck with those "low mids" they sell as subs.. and those "4000 watt" amps...
    Dennis, any thoughts.. that's all I can see... not flyable.. not much you can do with em that I can see...

    I have 4, 12" x 2" tops and 2, 2x12" subs and around 9000 watts that would crush that system...not trying to be mean.. but quantity here does NOT trump quality...

    For instance, 2 Peavey Q218 subs (with the right amp) would be so loud you'd never even know those 8, 118's were on...even wide open .. I fear you will be replacing a LOT of drivers...
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    DennisDennis Posts: 801
    Gadget wrote:
    Dennis, any thoughts.. that's all I can see... not flyable.. not much you can do with em that I can see...

    I think you pretty much covered it, Gadget.

    Shallom4usa, just to be clear, Gadget has suggested two tops per side horn up and two more tops per side horn down stacked on top of the first pair.

    I am going to take Gadget's suggestion on subs one step farther. Make a line of subs across the front of the stage. They can be 2' - 3' apart and still couple. Once you have a centered line, turn it into a smooth, rounded arc with the back corner of the outside subs touching the stage and the center subs 3' - 4' in front of the stage. You will have smooth coverage without cancellations.

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    shallom4usashallom4usa Posts: 26
    Thanks a lot guys, I've learn a lot and I will put them to use rightaway.
    So Gadget, the EP4000 has 1400Watts per channel @ 4 Ohms and the PV-215 are 700watts @ 4 ohms each, I thought 1 Amp should be enough for 4 tops ?.
    I totally agreed with you on my subs, I know they are cheap and only has 500Watts but hey! I'm just getting into the "game", I will definately be upgrading my gears as I move up. Also I just discovered that they are 8 ohms, looks like my calculation is off...hmmm...okay you gat me, I need more juice because EP4000 can only give me 750 Watts per channel @ 8 ohms. Thanks a million.

    On a brighter side though Denis and Gadget, do you think all what I have now is "OKAY" for a starter like me?
    I really cant afford to upgrade now, at least I need money rolling in first.
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    GadgetGadget Posts: 4,915
    Well, use what you have.. just do it smart.. limit the damage by setting the gain structure as per this thread:
    and when you come to the end of the power (the mixer gets even close to clipping after the gain structure) and you are OUT OF POWER...don't push it or expect limiters to protect the system...

    If it's for live sound you better leave a healthy margin.. like 8-10dB of headroom.

    The limiters on the amps are also going to limit the power available.. so use the gain structure and DON"T PUSH IT!
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    shallom4usashallom4usa Posts: 26
    You are the Man !!! Thanks for that word of wisdom, you do know your stuff. You guys are good, I mean really really good. I will update you after my first event this weekend. God bless.
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