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Rack 'em, cowboy!


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Our school has the following equipment:

Behringer EP1500 amp

Behringer EP2500 amp

Behringer DCX2496 Loudspeaker Management Unit

Behringer FBQ2496 Feedback Destroyer

Behringer FBQ6200 Graphic Equaliser


At present it’s all in a cupboard and gets brought out only for major events, however we now want to rack it up and mount it permanently in the hall.


Our commonest events are assemblies that use just one mic and a PowerPoint and/or video with-or-without a soundtrack. Occasionally the musos ask for a second mic. The proverbial hits the fan in drama productions when the mixer (Soundcraft) and the eight RF mics (Gemini ‘til Dec 2012) also come out along with anything else they ask for. This doesn’t happen very often.


In order to do this I propose to get:

Alesis MultiMix 8 rack-mount mixer

Art T8 8-channel rack-mount isolating transformers

Two 24-way patch panels


The T8’s outputs will feed into the mixer, the mixer into the ‘speaker Management Unit and hence to the amps.


The ensemble will “snake” to the AV control point where there will be sockets marked:

Microphone (mono, direct to the mixer’s channel #1 mic input)

Line 1 (stereo, jack switched to mixer’s channel #1 optional line input)

PC (Stereo via two T8 channels, mixer #2)

CD (ditto, mixer #3)

DVD (ditto, mixer #4)

Line 2 (ditto, mixer #5)

There will also be a few free channels of snake.


Management have asked for a Sky box to be installed and this will be in the cabinet and use mixer #6. I propose to install two channels of RF mic, mixer #7 & 8.


Everything will go through the patch panels.


The system will thus be set up for the uses most likely to occur: switch on, plug in a PC/CD/DVD and away you go; for anything more complicated plug in the Soundcraft mixer and patch it to the LMU, bypassing the MultiMix.


I run the power amps with their own limiters engaged. The other three Behringer units contain a variety of limiters, filters and so on, which I can have set up by someone who knows what they’re doing.


It can be mounted either backstage, 7 feet up the hall wall, or in an adjoining room. At floor level in the hall might be possible, but might not be wise.


Comments on this proposal would be welcome (PS. It’s a state school: don’t ask about the budget - a hollow laugh often confuses!)

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It'll be a heavy, and quite deep, rack. I'd have it on the floor, or supported via a solid shelf/bracket.


You have some fairly long unbalanced runs. Assuming the mixer has balanced inputs, I'd have the balancing trannies at the source end.

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Why not see if you can get hold of an old computer rack someone wants to get rid of.


The idea is, they usually have lockable(ish) doors all the way round, with the front door made of perspex so you can monitor what's going on inside without opening it.


That way you can keep out prying fingers whilst still seeing what's going on.

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Ditto the idea of an old IT bay frame rack for use for the drive rack (amps and system processing.) This doesn't need to be portable reading your descriptions of usage. Or get your technology tech to make a 19" enclosure out of some wood, and buy some rack strips to build your own. All you need to this is a left and right input - these can be run around the hall to the positions normally used for mixing from .


Then you need a rack for the 8 radio systems, if they aren't already racked up.


You don't mention the model of soundcraft mixer, but I am guessing that it isn't rackmountable. If it were me, I would avoid the Multimix, and buy something like an Allen and Heath Mixwizard3 16:2- selling the Soundcraft off if you need to raise more cash for it. Have this in a rolling rack with the mixer top mounted, and other equipment like CD, DVD, Sky, possibly a couple of the radio recievers.


I would also swap your FBQ6200 Graphic for a DEQ2496, have this in your rolling mix rack, and then you can run from your mixrack to your driverack using one AES/EBU digital link (if your cabling is good enough.)


Your profile is not complete, so I don't know where you are based. But you may find someone who is local to you and helpful may be willing to pop over and advise in person.

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Thanks for the replies.


Management told the IT chappie to install a Sky box in the hall, presumably to blight the calm of feeding time: "money no object". IT chap was doing fine 'til I asked "What amplifier are you going to use?"


For daily assemblies I wheel out a powered mixer, VHF RF mic and laptop and set it up; there's nothing installed. No way am I turning out every lunchtime to stand guard over it while 800 children screech their way through vats of stodge pudding. He ummed until I offered the Behringer stuff if he'd supply a cabinet for it - I've been wanting it out for ages. Caretaker had previously said it couldn't go on the floor as it would foul the space used by the canteen equipment at lunchtime. Luckily he relented when the contractor felt the weight of the power amps and said "Off the wall!" So it's going in a 30U rack cabinet screwed to the floor with a metal door so assorted brats can't see what's in it while queueing for their butties. I bet they spill drink on it.



The use of a simple rack mixer seems to me to be consistent with the "fit and forget" policy I'm following. The Soundcraft mixer I have would only be used for an event needing a comb of microphones (if you'll allow "comb" as a collective noun for mics). It's a Spirit 12, and Drama have an EPM6 I can borrow if I need a few more channels.



I agree that isolating transformers should be at the sources but most of these will be only three feet from the rack anyway. The lone scenario of a visitor wanting to use their own laptop at the front of the hall (50ft cable run) will be dealt with by a simple plug in isolator. I don't want to have to keep an eye on a lot of these: the rack mount option is secure.



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