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qsc rmx 2450 to 12 speaker setup.

Discussion in 'Tools Of The Trade' started by Steve Denenberg, Sep 17, 2012.

  1. Steve Denenberg

    Steve Denenberg New Member

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    I have a 3 rmx 2450's and i want to connect 12 b52 speakers,
    (12 inch) that are hung up around a bar. There are 4 powered subs also how can i connect them coming from a line mixer, like a dj mixer. I want to run all new speaker cable to them as well cause i dont trust the old ones they had. Its working hooked up booty style where it sounds good low volume but when we hook up the dj its shuts down gets hot etc. i would like a diagram of it or in simple terms. The speakers themselves have speakon connectors. I think the speakers are 8 ohms or 4 ohm. I think you can run 2 speakers to each channel on the amp i might be just stupid by asking how? thanks if you can help.
  2. Conanski

    Conanski Active Member

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    First thing you need to do is find out for sure if all the speakers are 8ohm or not, if they're all 12+1 boxes and have never had any of the drivers changed then it's a good chance they are but you need to know, because if some are 4ohm then you need more amplifiers.. period. You're also going to need an active crossover to split the signal form the mixer into highs and lows, a DBX223XL will suffice here and it connects between the mixer and the first amplifier with XLR cables. The speaker connections will be pretty simple you just run a single cable from the L and R amplifier outputs(speakon) to a pair of mains and then make a jumper to go from the second speakon connector on those speakers to the nearest speaker, and the other two amplifiers are configured exactly the same. I'd also suggest you use 14ga install speaker cable for this and not regular speaker wire, the install cable has shielding and is usually brightly colored to differentiate it from other cables.

    The DBX crossover has a mono sum feature for subs so that's why there is only 1 XLR cable going to them. The jumper cables between amplifiers are XLR to 1/4" TRS, this is an easy way to get the same signal to all them. Make sure the dip switches on all amplifers are set the same and that they're set for stereo operation(not bridged) with clip limiters engaged.

    Attached Files:

    Last edited: Sep 17, 2012
  3. Steve Denenberg

    Steve Denenberg New Member

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    amazing. heres my reply

    thanks for the response, my issue is that i dont have dbx crossover. the back of speakers only have one speakon connector not 2. dont really know what a jumper looks like , and dont want to use the speakon on amp want to use bare cables to posts. sounds stupid but i gotta use what i have at the moment. Your advise makes sense except for the above reasons, i work at bar as the dj and the system just needs some help and its been a mess. but i fell i can do it, its just waiting for the checks and authorization signing etc bull thats making it take so long. But any more advise would be great. like what a jumper looks like, and minus the dbx, thanks a million wish i could just have you do it lol. steve denenberg . i havent found out if they are 8 or 4 ohms i thinks its 4, the qsc people told me i can run 2 speakers per channel meaning 4 per amp and run at 2ohm. so i want to go that route maybe seems like yours is the same no?
  4. Conanski

    Conanski Active Member

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    Not having a crossover complicates the wiring you're gonna have to do but there may be another way to get the same functionality, do the subs have a high pass output? If they do then run a pair of XLR cables from the mixer location out to the sub nearest the equipment, and then a pair of XLR cables back from that subs high output to the first amp in the stack. The jumper cables between the amps are XLR to TRS which can be purchased at any pro audio shop or ordered online, and connecting the speaker cables directly to the amp terminals is fine for an installed system like this but it means you're gonna need a lot more cable because all runs have to go back to the amps. Hopefully your speakers are not 4ohm versions though, QSC makes very good equipment but even these things aren't really meant for sustained 2ohm operation.
  5. Steve Denenberg

    Steve Denenberg New Member

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    you the man

    um there are 4 subs
    1 ev
    2 qsc
    1 b52
    i have seen this i think one of them does have this
    but i need a simple solution. i am afraid the speakers are 4 ohm ill wed morning when i go in, i was wondering what would be good chap cable to run to speakers and where to get it in a spool or measure the exact lenghth.
    any other ideas i like to present them to the manager. you drawing was perfect but what does a jumper look like is that like splicing 2 cables together.
  6. hippydog

    hippydog wuz here when it was Red.

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    give us the EXACT model numbers and QTY of the all the equipment you do have.. (amps, speakers, mixer, etc)
    take pictures

    draw a diagram of where everything is located..
  7. Bob Dietrich

    Bob Dietrich New Member

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    This sounds like a total mess! 4 subs from 3 different brands....PUNT!!! ;)
  8. Conanski

    Conanski Active Member

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    A jumper is just a shorter version of a regular cable, but you can forget about this because if the speakers only have 1 input then you can't use jumpers.
  9. djtunes

    djtunes Checking Reality

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    You could wire 2 speakers bare wire to each binding post terminal (Be sure for sure for sure that you have the right + & - wires connected right) with a total of 4 speakers IF they truly are 4ohm speakers. If you know they're 8ohm you could get away with 3 per side, but with only 4 subs I think you only need 4 tops unless the coverage is hard to even out. JMHO

    The way that ohms thing works, simplistically, is: when the amp is running in normal stereo mode it is able to handle loads as low as 2 ohms on each channel (channel 1 & 2). The speaker specs. & config. determines what the load is. A 4ohm speaker makes the amp see a 4ohm load. 2 4ohm speakers attached parallel (which is the way were discussing things now) results in a 2ohm load on the amp. At that level it is simple enough to understand.

    The back of the amp has a few good features.
    #1 The dip swithches that say parallel allow you to plug just one mono signal into the amp instead of using 2 cables. If your mixer is capable of mono output this would be ideal. You can send the same signal all over the bar without losing any parts of a true stereo song, plus it allows you to use your other mixer line out to go to the subwoofer chain of speakers. If you have no way of playing mono, nevermind about that one.

    #2 The dip switch that is for clip limit. Turn it on. It will help prevent distorting and help the speakers live longer plus help things sound good even at high volume by helping to prevent sound distortion. Turn the clip limiter on.

    #3 The dip swithch that goes between 50hz & 30hz filter. Switch it to 50hz filter. Especially since you say you don't have a crossover this will keep most of the SUPER LOW bass out of your top boxes. Those speakers probably are not made to hit below 50hz anyways, and music that goes that low/deep pushed into speakers that don't like it is not a good thing. You'll damage the speakers with a low note that you didn't even hear.

    #4 The Bridge Mono switches MUST MUST must be set in the off position, switched to the left/OFF position. If that ain't set right you're screwed.

    I have an RMX amp and I know that when you're behind the amp trying to switch those tiny switches it ain't always easy to see them. If it's hard to get a really good angle to see them really well wherever the amp is mounted, I'd suggest taking the amp out, setting the switches, then put it back knowing 100% that you have it set properly. I use either a small tip screw driver or a key with a narrow end to switch those tiny switches. Sometimes you think you're seeing them good but the top switch is just a little out of view and can mess you up. Get a good look at it and after setting them look at it again to be sure you got it right. Maybe use a flashlight or your phone to get some light on it.

    I'm gonna make a statement that assumes that the system is being used in a single room, and that the speakers are placed strategically to create good coverage for all of the areas of the room.

    With 4 subs, you only need 4 tops. More tops playing at high volume are going to over power the subs.

    Speaker placement is important. A drawing of the room including the locations of things like the dance floor, the bar, pool tables, dart boards, etc. would be useful if you want advice. I say keep the 2 QSC subs at the dance floor sitting side by side, with 2 of the top boxes elevated about 6' or more there either spaced 20' apart or sitting side by side angled away from each other by about 45 degrees.

    Then the other subs at 2 other places (maybe far corners) with a top box placed above each one of them.

    Like I said, without knowing the room a lot of that could be way off. I'm thinking you don't want speakers BLASTING the actual bar area because when the music is loud it makes it harder for the servers to communicate with the customers. You might end up wishing it was louder somewhere else but the volume is too loud already near the bar.

    Maybe put the 2 speakers closest to the dance floor on one channel, and the other 2 in other spots wire to channel 2 so you can set the volume on the dance floor separately from the others.

    One last piece of advice. Set the mixer so it will not clip the amp like this: With the amp and mixer turned down... Play a loud hard hitting song like Low by Lil Jon... Turn up the mixer to the point just before it goes into the red on the volume or DB meter. Then go to the amp and turn up the gain knob there until the clip light starts blinking and then back it off a hair to make it stop blinking. If you mess with the bass and treble on the mixer of EQ you should re-check this "gain structure". Do the same with the subs too. Then you'll always know that as long as you're not too high on the mixer meter the amps are not being over driven.

    Once you know the maximum output ability of each section you can adjust the sound to your liking. Common sense says that if there is too much highs when the subs are hitting their hardest to the point of clipping you turn down the amp going to the top boxes, or turn down the highs on the mixer. Same goes the other way too. Not enough top end... lower the sub amp's gain. If you have too much of this (whether it be bass, treble, highs) and not enough of that don't increase the EQ. Instead turn down the overpowering section. Every time you go up on an EQ you're adding distortion and opening the window for damage so try as much as you can to fix it by turning stuff down.

    Make sure the amp can breathe, especially make sure it can get cooler/room temp air in the back. Dust it if it is getting dusty inside.

    I guess that's all of the input I have for now. I know it's tough when you don't have unlimited resources to do a set up. Hopefully all or part of this helped.
  10. Steve Denenberg

    Steve Denenberg New Member

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    ok heres the layout.there are a couple speakers i unplugged cause no tweeter. The speakers are 4ohm and rated 300 watts 15' b52's. I just found out and went to get repaired was rmx 2450 fan wasnt spinning dammit. anyway. I think the dip switches are no all on stereo clip limiter on , bridge off, and a few other cant remember but i think its right maybe a tweak here or there. Out of the american audio mixer main xlr's into a stereo behringer eq out of the stereo xlr, into amp 1 with xlr stereo, out with 2, 1/4 cables to xlr stereo, into amp 2 xlr's stereo. The speakers cable out wall only comes out as 4 cables. meaning i took those 4 cables and plug them each into theyre own post positive negative on each so now i got two amps going with all the speakers working except subs, weird, i think i know whats going on. well on the amps i can turn up the gains and hear what speakers are going , i guess im gonna have to figure how many are on the line at once connected to that channel right and make sure there is not more than 2 speakers per channel connected on the same cable, sound right?[​IMG]
    Last edited: Sep 20, 2012
  11. djtunes

    djtunes Checking Reality

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    I'd try to get all of the subs on the floor to get the best sound out of them. 2 matching subs at the dance floor sitting side by side. When you set them up against each other side by side it's called "coupling" and you get more output. Picture an example by dropping 2 rocks in water apart from each other and watch the waves defeat each other when they meet, or drop them in the water same spot side by side and watch one bigger wave that goes farther.

    The sound also move across the floor, but on the ceiling you're probably losing a lot of bass.
  12. hippydog

    hippydog wuz here when it was Red.

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    With 12 speakers its most likely they wired it 3 speakers per channel.. (easy way to find out is connect just one cable and see which speakers work, then do the same for the other 3 sets)

    Can you take a picture or figure out how they wired them?
    I'm curious if they ran them in parallel or series..
    in Series it would be 12 ohms (which isnt horrible), and in parallel it would 1.33 ohms (below the capability of the amp)

    in your first post you said they had 3 RMX amps right?
    do you know what they were using the third amp for?

    or do you think all three were used to power the tops?

    Also I still need to know the models of the subs..

    and third.. can you also check to see what kind of power is being delivered to the amp rack and subs..
  13. Steve Denenberg

    Steve Denenberg New Member

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    reply tyo my post thank you

    um i will the sub models tonight, i can take a picture of the amp rck setup but the speakers would kind of hard to explain.lol i dont know what series is or parrallel. i have an idea dont know the difference. amp load they split the breaker they said so now it runs at like 29 amps but there is alot of stuff plugged into it. i wll try to take a sub off the rafter and put it in the dancefloor by the other one just dont now if the breaker will handle it, it has one on there already. i was just gonna run new speaker cable to each speaker then run 4on one amp4 on the other 4 on the third amp. the run the subs out of the 1/4's on the third amp coneecting the dancefloor to one channel then 3 to the other by daisy chaining them. i might work . but well see. i have to get the other amp back from qsc. but daam the weekend is here, I might go tonight when other dj is there and stay after and get into it a little more
  14. hippydog

    hippydog wuz here when it was Red.

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    www.installdr.com/TechDocs/999016.pdf
    big thing is this document has pictures, which might help in figuring it out..

    the cords have two wires each correct?
    ones positive and ones negative (it may be a black and white wire)

    What kind of connectors are on the back of the speakers? 1/4" phone? Neutrik NL4?

    Also can you find a model number for the B-52 speakers.. On the B-52 website, all their individual (non matrix) speakers are 8 OHMS... so my first thought is.. are you 100% sure this speakers are 4 ohms?

    so again..
    manafacturer, & model of ALL THE SPEAKERS is pretty important.. if you cant get the model (IE the id plate is ruined) then take a picture of the back and front of the speaker..

    does this site still allow uploading of pictures??? if not you can email me at hippydog@yahoo.com



    29 is an odd number.. but if they add three rmx amps in there they should have had at least three 15 amp ccts or a split 30 amp.. its probably fine but I wouldnt add any more stuff to it for now..



    leave the sub where it is.. if you want to make slight improvements later, then fine.. but dont start introducing more problems until you have the basics figured out and the system running..
    This is not a mobile system, lots of bars run their subs in the roof.. 1.) because thats the easiest place to run wiring, and 2.) floorspace is usually more important then a few extra db of sound..

    that would be ideal of course..
    but , i think you mentioned you didnt even have an active crossover in the system?

    cost of wiring up each speaker with its own run (correctly as in proper awg, not looking like a rats nest, etc etc) will most likely cost a lot more then a regular active crossover..... just sayin..

    if it was me..
    I would first figure out the system and how they ran it and wired it..
    then I would getting every thing working again, correctly..
    then I would start making improvements, (run all the subs in mono off an active crossover, decide if the tops can be moved to better locations, rewire and reorient the speakers so the bar is "zoned" , etc etc)
  15. djtunes

    djtunes Checking Reality

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    Cheapest place to get a lot of wires...

    monoprice.com

    I've ordered from them. The product is quality made right at their factory.

    If you go to that site you'll probably be surprised what you really can afford.
  16. Steve Denenberg

    Steve Denenberg New Member

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    thanks for reply.

    i dj tonite there so i will get a good idea of what it sounds like loud. the back of speakers says 4ohm 300 watts thats it, i havent taken any pictures yet i keep forgetting, um the dj last night said no clipping no dropouts worked great but i have to see for myself. I am so gratefull to you all who have chimmed in. It really helpful. well one amp the fan wasnt working so i took it back to qsc get it repaired. So i really dont want to do anything till i get it back after weekend. Basically i am almost there im wondering if putting a fan on the back rack will help like a vornado fan not a box fan , just to move air in the back of rack, um any other ideas totally help thanksguys
  17. djtunes

    djtunes Checking Reality

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    A $15 fan from walmart will move the hot air away from the amps.
  18. hippydog

    hippydog wuz here when it was Red.

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    well, then that seems pretty definitive then! :)

    then I would say your next step is to start tracing the wiring.. (make sure which speakers are connected to which wires)

    I would also be interested in the direction the speakers are facing, as your diagram was a little unclear on that.. (again, a picture is worth a thousand words)

    did you say you got the subs working or no?
  19. Steve Denenberg

    Steve Denenberg New Member

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    thanks for reply.

    pointed at the amps from the back. should i be getting yellow lights on the front of the amps?
    mellow yellow then turn up knobs they get brighter. , i will keep the gain from my mixer into rack at green to yellow then out of rack mixer yellow green not red then turn up amps as i go separarting the zones into 4
  20. djtunes

    djtunes Checking Reality

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    When the music is playing the yellow ones are blinking (right?) which indicates you're getting a signal, the red light is the Clip light and it should only be blinking on the hardest hitting song only in the most extremely demanding situation. In reality it is ideal to never let those lights come on, but sometimes when you're really pushing the amp it might happen. Slightly blinking a clip light at the most extreme volume demands is acceptable, but a constant red light is not a good sign, and can lead to damage. A signal that is clipping is basically going beyond the natural range of the original audio signal, and can produce sound levels, and sound waves that will damage your speakers, and will just sound like crap coming out too. Plus you're risking frying your amp. Rule of thumb is to stay out of clipping (meaning stay out of the red) on all connected equipment that has any type of VU meter, level indicator, or clip lights. Including the mixer, EQ, crossover, amps, powered speakers/subs, and anything else with a volume, or gain control.

    If you're not getting enough volume out of any specific sound system without clipping then you need more power, and/or more speakers.

    It can be a headache setting up a system to stay out of clipping, but having another user come in and max out the volume at the mixer so it's clipping anyway while you're not there. Maybe you should tape a note to the mixer near the VU meter that says "DON'T LET THIS LEVEL GO IN THE RED - DON'T CHANGE ANY OTHER EQUIPMENT SETTINGS." Just by turning up the bass you can send things into clipping.

    Good luck.

    Oh yeah! Here's a link to the user manual for your QSC RMX amps: http://media.qscaudio.com/pdfs/manuals/RMX_User_Manual.pdf
    Maybe print it out when you can, and leave it with the amps.

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