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LCR Application

jjaynejjayne Posts: 3
edited May 2007 in 4800 General Discussion
I am the technical director for a church that is building a new facility. We have a FOH design that includes LCR bi-amp or possibly tri-amped mains, front fills and subs (12 boxes in all, quad amped plus fills). I originally was looking at the driverack 480 series for DSP, but now I wonder if the 4820 would be a better solution. If so, how would I configure such a system using the 4820(s)?


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    GadgetGadget Posts: 4,915
    I'm not sure i have all the info I need to help you but you need to know that the 4820 is NOT a stand alone unit.. It needs a computer to run the GUI.. Ok so you knew that already perhaps. The 4800 series is essentially the same input and output wise as the 480... it just has 96 khz capability and more flexible routing and some more current control capabilities like Ethernet Hi Q net, and optional Cobra net. The 4800 has a full color stand alone capability, but the 4820 has no control surface.

    You have 4 inputs which could run L/C?R and 1 zone/fill/subs.. etc.

    If you biamed the tops and had subs you would run (for instance) inputs 1-2-3... as L-C-R respectively and have outputs 1-2 as the lo and hi for input 1, outputs 3-4 for lo and hi for input 2 (CTR), and 5-6 for input 3 lo and hi. That leaves 7/8 outs for subs and or a Lo mid out that could run off any of the inputs.. 1-2-3-4...

    Your post doesn't really make it clear what exactly you are trying to do, so if this isn't the info you need please be as specific as possible as to what you have and what you want to do. Please include speakers, amps, subs, and configuration details like speaker locations and coverage patterns if possible, room size and any potential problems with the room. Please include desired coverage and potential needs if the EQU isn't purchased yet. This is an information intensive process and too much is never enough.
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    jjaynejjayne Posts: 3
    Thanks for the reply.

    I realize that pretty much anything is possible with the dbx driveracks but I have only ever worked with single units. I will be looking at using the 4820s since they will probably be mounted in the amp racks. I will be using a PC to control them via a dedicated LAN.

    The room will be 80'x 60' with a 24' Stage on the one end leaving us an almost square house (56' D x 60' W). The ceiling is an open scissor truss (24\" on center) with 18' to the bottom of the truss on the outside walls and 25' to the bottom of the truss in the center of the room. The trusses are parallel to the leading edge of the stage.

    We have a LCR FOH design that includes 4 bi-amped EAW AX364, 4 EAW MK8196 front fills and 4 EAW SB1000 subs (12 boxes in all). The Left cluster will have a AX364 and a MK8196 Fill hung directly below the AX. The center cluster will have 2 AX364 with 2 MK8196 fills. The Right cluster will be the same as the left cluster. The LCR clusters will be flown from the scissor truss. The Left and Right clusters will be about 15 feet from the Center cluster (30 feet from Left to Right). The four subs will be mounted under the leading edge of the stage, problably two closer together in the middle of the room and the remaining two further apart possibly under the left and right clusters.

    We will be using QSC PLX2 amps for all the speakers. One amp for the Left and Right Highs, one amp for the Center Highs (parallel), one amp for the Left and Right Lows, and one amp for the Center lows (parallel). The fills will be amped in the same fashion, one amp for the Left and Right fills and one amp for the Center fills (parallel). Each sub will have it's own bridged mono amp. 10 amps in all.

    The FOH console will be a Soundcraft MH2. If I explained this correctly, I have three inputs and 13 outputs (if I count each of the four subs as single outputs).

    I hope this gives you a better idea of what we are trying to do. Thanks for your help.
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    GadgetGadget Posts: 4,915
    Hi I'm working up something but I just got a 4800 myself and I want to get a little more familiar with it first.. as I see it though L and R will require all 8 outputs on 4820 #1 and CTR will require 6 outputs on # 2, this way you will be able to steer the subs... IF they are tight together under the stage. This will allow power shading for the front rows if you use a channel for each ctr downfill.

    It would be something like this:
    4820 #1
    input 1L, input 2R, input 3CTR, input 4 subs

    Output 1 L hi
    Output 2 L lo
    Output 3 L downfill
    Output 4 R hi
    Output 5 R lo
    Output 6 R downfill
    Output 7 L sub
    Output 8 R sub

    link units
    4820 # 2

    Output 1 CTR hi
    Output 2 CTR lo
    Output 3 top downfill
    Output 4 bottom downfill
    Output 5 L CTR sub
    Output 6 R CTR sub

    Feed the subs off one of the auxes routed through one of the VCA's then only send what you want in the subs through the auxes, and engage the HPF on all other channels and set HPF on all other channels and use the CTR point for setting the frequency of Lows you want for those channels.

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