# How to Hook Up



## getmandc (Jun 5, 2013)

So I just got a call from a friend who is opening up a new club sports bar and asked me if I could be his DJ for the weekends. I said yes.

He told me that his club sound system was:

4 JBL JRX125 loudspeakers (stacked 2 left/2right 
1 Yamaha Emx 5016 (16-input, 500W per Channel Powered Mixer) 
1 QSC GX series amp (not sure which one but its likely the gx3) 


[IMGL]https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcQHBz1XRatQtMNKh7KGQXyYljYRJ5wKqOnSnI4Wk8Dj8WC_AQbUUA[/IMGL]








He also told me that I would have to wire it up and bring my own wires. I have always been a mobile dj so all my speakers are powered. As I started looking owners manual for the QSC GX I seen there was multiple ways of hooking up these speakers and it has to do with ohms and loads and so I thought I should get some help from someone who is more experience as to how I should hook this up and what types of cables I should use.

My game plan is to hook up:
1 left and 1 right JBL speaker to the outputs on the back of the Yamaha using speakon-speakon cables
Hook up the Yamaha to QSC GX amp with ST outs on Yamaha using 2 1/4"-XLR cables (1 for each channel)
Then hook up the remaining 2 speakers using speakon-speakon cables from the back of the amp using channel 1 for the left speaker and channel 2 for the right speaker

I figured that this is the best way to do it.

Now however the bar owner told me that he maybe getting a pair of Harbinger HX118s subwoofers so to bring the xtra cables just in case. Adding those two extra subs in the mix just completely throws me of on what cables I need and how to hook them up.

So my first question is the way I have it set up for the first installation correct.
My next question is what is the best way to hook up everything including the subwoofers?


[IMGL]http://data.yamaha.jp/sdb/local/products/images/11362/12075/11362_12075_1.jpg[/IMGL]


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## gafftaper (Jun 5, 2013)

You are going to need a second amplifier to power those subs, they are way to thirsty for power to just add into the existing gear. You also need a crossover to split the sub signal off of the main output signal.

Out of the mixer into the crossover. Then one line goes to Amp A and on to the mains while the other line goes to Amp B and on to the subs.


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## getmandc (Jun 5, 2013)

gafftaper said:


> You are going to need a second amplifier to power those subs, they are way to thirsty for power to just add into the existing gear. You also need a crossover to split the sub signal off of the main output signal.
> 
> Out of the mixer into the crossover. Then one line goes to Amp A and on to the mains while the other line goes to Amp B and on to the subs.



I can get a QSC GX5 amp for $300 bucks. These amps come with a built-in cross-over feature?

How would I hook up the mixer to both amps?
How would I hook up the amps to all the speakers?

Also I am not sure if the owner is willing to spend on an amp and he is going to be shocked when I show him the bill for the cables. 

Is it better for me to leave out the subs then if I cant get an amp?


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## DuckJordan (Jun 5, 2013)

They cross over on the amp runs only one channel, you could run a gx5 without the crossover but it'd likely sound bad.


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## NickVon (Jun 5, 2013)

getmandc said:


> I can get a QSC GX5 amp for $300 bucks. These amps come with a built-in cross-over feature?
> 
> How would I hook up the mixer to both amps?
> How would I hook up the amps to all the speakers?
> ...



You can power the 4 jbl JRX with your two outputs on the console. (remember you can daisy chain your two left and two right together in series. This does change your impediance so you would want to check what your output of the console is for 4 ohms on each output. That said now need to use both pairs I think one would do.

Then provided you got some sorta of outboard EQ (31-band/15) or at worst A parametric) you can through tha on an Aux output feed the output of hte EQ to your QSC amp, and feed your subs. THen the Aux 2 Master becomes our sub woofer control. The EQ is to protect your subs and cut out any frequencies that it can't produce. a "crossover" is more specialized and is something that i don't think would work as well with the current powered console you have available. A simple EQ, and 4x Speakon cables seems like it would get the output side of your system up and running. Ebay is your Friend. Also I can't imagine that speaker cable should run that much unless you are running really long distances to your mix position.


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## museav (Jun 6, 2013)

Let me understand, your friend is opening a new venue, has some existing audio equipment, asked you to DJ on weekends and then said that as part of that you have to hook up the sound system and make it work including using your cables? And you refer to this as an install, thus apparently intended to be permanently installed.

First, installs are different than portable setups in that building codes can apply. That means things like some cabling may have to meet certain ratings and be installed in a certain way, extension cords may not be allowed for power, gear can't interfere with access or egress and so on.

There also seems to be all sorts of details to be established. How and where are the amp and mixer mounted? Are the speakers stable when stacked? Is this new or used gear and has anyone tested it to be sure it works properly? Are they going to compensate you for the install effort, your cables, etc. or are you donating that to get the DJ gig (and might that be ended soon after you've completed the install)?

Has anyone assessed whether the equipment is appropriate for the application? Does adding Harbinger subs to the existing dual 15" boxes make sense and might there be other equipment required to make that work? Why two JRX125 stacked on either side and if they are truly stacked then can you just use the top one or trade those in for two better speakers or two mains and two subs? If the system does not perform as they expect are they going to look at that as being your fault?

Then there is what liability you are assuming. What if someone else uses the system and something fails, are they going to expect you to take care of that? What of the speakers fall over and something is damaged or someone is hurt, are you liable? By being the one who installed it are you essentially going to "inherit" responsibility for the system?

The bottom line is that you are a DJ, bring the cables to connect your gear to their system but keep the installation of the house system separate.


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## getmandc (Jun 6, 2013)

museav said:


> Let me understand, your friend is opening a new venue, has some existing audio equipment, asked you to DJ on weekends and then said that as part of that you have to hook up the sound system and make it work including using your cables? And you refer to this as an install, thus apparently intended to be permanently installed.



I guess a more appropriate subject title for this article would have been cabling but I couldn't find it and install looked like the next best match.

So after the advice I was given on this forum I went down to the bar and let the owner know that he was going to have to buy cables and new amp if he wanted to run the two subs with enough power to sound good. He gave me the money for 4 speakon-speakon cables to hook up the the powered mixer and amp to the 4 JBL JRX125s. Everything sounded good and was working fine. The mixer sits atop a mobile black and silver rack mount. The amp is bolted inside this rack mount. The rack mount has 4 or 5 more empty slots.

Now this guy has hired me to DJ but he is extending that definition by making me in charge of getting his sound system running. In small towns with small club sportsbar applications like my current situation it is not uncommon for the DJs to also be the ones who run the sound systems and are in charge of making sure its running and sounds good. If the system doesn't perform as it should then yes it will be my responsibility to provided the manager with the necessary information to get in running as it should. Please remember that although this is going to be a business, it is an entrepreneurship that this guy has decided to launch with limited funding and looking for help in the areas he is not an expert in. He is aware that I am no sound engineer or professional contractor with years of experience in club installations but he has asked me to help get his business going with him and is willing to pay me a fair amount so now I am here. I apologize if this is a forum for professionals only.


museav said:


> Has anyone assessed whether the equipment is appropriate for the application? Does adding Harbinger subs to the existing dual 15" boxes make sense and might there be other equipment required to make that work? Why two JRX125 stacked on either side and if they are truly stacked then can you just use the top one or trade those in for two better speakers or two mains and two subs? If the system does not perform as they expect are they going to look at that as being your fault?



Well to answer this question is the reason I joined the forum. I guess you are just better at asking the questions than I am but as I get more familiar and educated with the ways of the forum and the trade I will be able to come straight out and as what needs to be asked. In my case I just figured I ask the basics on how to hook it up and figured if anyone had better ideas or if I was doing something wrong they would point them out and give me advice. 

You did bring up some great points about other DJs and liabilities that I am going to be sure to discuss with owner.


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## museav (Jun 7, 2013)

getmandc said:


> Now this guy has hired me to DJ but he is extending that definition by making me in charge of getting his sound system running. In small towns with small club sportsbar applications like my current situation it is not uncommon for the DJs to also be the ones who run the sound systems and are in charge of making sure its running and sounds good. If the system doesn't perform as it should then yes it will be my responsibility to provided the manager with the necessary information to get in running as it should. Please remember that although this is going to be a business, it is an entrepreneurship that this guy has decided to launch with limited funding and looking for help in the areas he is not an expert in. He is aware that I am no sound engineer or professional contractor with years of experience in club installations but he has asked me to help get his business going with him and is willing to pay me a fair amount so now I am here. I apologize if this is a forum for professionals only.


Not at all a forum for professionals only. A startup having limited funding and looking for free or lower cost help is common, however that does not change that it is a business and the space a commercial occupancy and thus it is a professional application.

Personally, I would only use two of the JRX125s. Using two stacked is usually going to result in all sorts of combfiltering, boundary cancellations from the floor, etc. with limited actual benefit. Maybe just disconnect the top and then the bottom and see if it sounds better with just one or the other.

I personally don't understand using dual 15" mains with subs, in fact the JRX125 uses internal circuitry that only uses both 15" drivers at low frequencies and rolls off one of the 15" drivers at higher frequencies, essentially one 15" driver serves as an internal subwoofer, and when high passed to be used with a separate subwoofer the one 15" driver does very little. If you use subs then one mains speaker per side with a single 15" or 12" woofer would have cost less or allowed you to use better gear and quite likely would sound just as good or better, but the stacked JRX125 probably do look more impressive and for some music genres appearance probably matters as much if not more than the sound quality.

Speaking of high pass, if you add subwoofers then you need to send just the low frequencies to the subs and only everyting above that to the mains, in other words a crossover. Some subwoofers have a simple crossover built in, you run the amp output to the subwoofer and then the signal loops to the mains with a single amplifier driving both. However, apparently the Harbinger HX118S does not have any integrated crossover or flitering. That leaves you two choices. One is that some amplifiers have integrated crossovers, either simple high and low pass filters or more advanced integrated Digital Signal Processing. You take line level out of the mixer to the amp and appropriately setup the internal crossover in the amp. The other is that you could use a crossover or system processor between the mixer's line level outputs and the amplifier inputs. In both cases you would then have to properly setup and adjust the processing applied, match amp levels, etc. It should also be noted that because the amps in the Yamaha powered mixer do not appear to have a way to insert any processing and the Harbinger subs do not have an internal crossover, then if you add those subs you pretty much don't want to use the amps built into the mixer.

That is just one reason you may might want to seriously rethink the subs. In addition, have not gone though all the math since I don't know the specific amps involved, etc. but just in general the specifications for the JRX 125 are a frequency response of 35-16kHz (-10dB), a sensitivity of [email protected]/1m and a maximum output of 133dB at 1m. In comparison, the specs for the HX 118S are a frequency response of 32-250Hz (no limits provided, so I would assume -10dB), a sensitivity of [email protected]/1m and a maximum output of 128dB at 1m. Now real world results are going to vary but based on the specs and how you would have to connect everything, you basically may be incurring additional costs and potentially taking a step back in performance.


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## getmandc (Jun 7, 2013)

Thanks for the information,

So what I got from this is: 


stacked JRX125s result in sound quality loss
having the JRX125s crossed over with subs negates one of the 15s
taking out a pair of JRX125s and adding subs will result in better sound quaility

I think I have a solution to each of the points you brought up but please correct me if i am wrong:

The amp I am using is a GX3 or GX5 I am not to sure which one but it does have a crossover feature. The crossover point is 100Hz but limits the low-pass filter to only one channel. Multiple subs can be hooked up to that one channel.
Now in order to keep the JRX running like they should I could hook both of them up to the full range output of the Yamaha mixer.
Then I can hook up the subs to the low-pass channel on the GX series amp
Ill stack the the JRX125s on the subs and leave the other pair of JRX125s out of the equation maybe Craigslist. Since there is still a second channel on the amp not being used I can use one of the JRX125s as a temporary booth monitor or floor wedge.


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## museav (Jun 8, 2013)

getmandc said:


> Thanks for the information,
> 
> So what I got from this is:
> 
> ...


If you use the one channel of the GX for the subs then you would usually want to use the other channel, set as the corresponding high pass, for the mains. Then maybe set the amps in the Yamaha to Aux 1/Aux 2 mode for monitors, although they would have no EQ. However, because your JRX 125 mains are nominal 4 Ohm rated you would not really want two in parallel on one channel of a GX amp so that approach might require at least a second GX amplifier. 

I would also tend to try the system with and without the subwoofers, given the differences in response and sensitivity versus the JRX125 I'm not sure you'll gain that much with the Harbinger subs, but it seems worth verifying before committing to anything. In fact since you have everything I would try different combinations and see what works best. Sometimes what would likely technically be the better approach may not be the one you or the Owner like the most.

I'm hoping others will add their thoughts.


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