# Two channels on one NL4, is this correct?



## tk2k (Nov 1, 2012)

Hi all,
stupid question here... I'm trying to use one 4-wire cable to carry two independent audio signals. 

I have 4-wire speaker-grade cable, i've wired 2 channels of my amps to the nl4 (channel A is -1, +1, B is -2, +2). Then, when I get to the speaker end (th-115 with two nl4 jacks) i assume the speaker will source only from pins +1 and -1, then I go out of the 2nd port on that speaker and route connect pins +2 and -2 to +1 and -1 on the second speaker, correct?


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## Call911 (Nov 1, 2012)

Yup. Looks right to me. If it were me I would make it idiot proof and reroute the connections inside the second speaker to 2+ 2- also. This way of the wire gets plugged into the second speaker first, it still gets the correct audio signal. I use this for portable stacks that have separate subs and fulls. This way no matter how a stage hand plugs it in, it won't hurt anything and still gets the right signal.


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## Footer (Nov 1, 2012)

Yes, that will work. Some gear is actually set up this way. D&B does this on some of their boxes. You will have to label your gear correctly and all that fun stuff. What the NL4 is supposed to be for is supplying power to a bi-amped speaker with just one line.


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## gcpsoundlight (Nov 1, 2012)

I have seen a switch on some JBL Boxes that allows you to select which pair it uses, and it passes through both pairs.


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## tk2k (Nov 1, 2012)

Gotthca, good suggestion Call. I'm actually powering two subs in a stack that wont' always be used (i.e. might use one sub alone sometimes) and wanted to make sure that if the stagehand forgets to turn off the 2nd amp I wont' be driving 2x the power my sub wants. 

Thanks guys


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## Chris15 (Nov 1, 2012)

I think it was JBL a few years ago made a 2m cable with orange NL4s on it that was a pair reverse designed to be used in this sort of situation with whichever of their boxes.
Ever since I've assumed orange Speakon meant pair reverse or something else funky going on...

JBL also made a box or two at times that has a biamp / crossover switch on the back, so just be careful and check what the switch does before you use it 

If it were me, I'd be keeping all of my inventory wired for pair 1 active - it's just more versatile that way.
Then get some non standard coloured cable to make some pair reversers in fairly short lengths...
But that's just me and my way...


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## Footer (Nov 2, 2012)

Chris15 said:


> I think it was JBL a few years ago made a 2m cable with orange NL4s on it that was a pair reverse designed to be used in this sort of situation with whichever of their boxes.
> Ever since I've assumed orange Speakon meant pair reverse or something else funky going on...
> 
> JBL also made a box or two at times that has a biamp / crossover switch on the back, so just be careful and check what the switch does before you use it
> ...



Better idea. Easier to change a cable than change a pin-out on a box. The way D&B does this is all of their top boxes use the 1st pair, all of their bottom (sub) boxes use the 2nd pair. When you setup an amp it knows how this goes. It is not a bad idea to adapt gear to this "standard". It all depends on how your boxes are deployed and how you do your processing.


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## bishopthomas (Nov 2, 2012)

JBL SRX and VRX subs allow for setting the box to receive from pins One or pins Two on the NL4. Most modern amps (at least Crown and QSC) are set up so that pins Two of the amp's channel 1 output will send the amp's channel 2 signal down the NL4. So we run our VRX rigs with the subs set on Pins 2. Then one NL4 cable goes from Amp 1 Channel 1 to the left sub, then the subs jump to the tops (2 conductor cable is fine for this but we've found it's easier to keep one type of cable in stock). Then Amp 2 Channel 1 goes to the right subs then jumps to the tops. So, to reiterate, Amp 1 is House Left, Amp 2 is House Right. Channels one carries the signals for the tops, channels two carries signals for the subs.

To complicate things further, you can use an NL8 cable for more complicated systems with breakouts to go to NL2/4. We had CBI build some custom breakout boxes so that we can run a single NL8 and have a pair of biamped monitors, 4 passive monitors, a zoned FOH system, etc.


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## DuckJordan (Nov 2, 2012)

Just so you are aware, unless the subs are sperated (different box) or they don't share a port space then you may be damaging your cones.


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## museav (Nov 3, 2012)

Have you contacted Danley and asked how the NL4s on the TH-115 are wired? You might assume 1+ and 1- are used for the box (and I believe they are) and that the two NL4s are wired in parallel with but I wouldn't proceed without first verifying that to be true.


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## tk2k (Nov 3, 2012)

museav said:


> Have you contacted Danley and asked how the NL4s on the TH-115 are wired? You might assume 1+ and 1- are used for the box (and I believe they are) and that the two NL4s are wired in parallel with but I wouldn't proceed without first verifying that to be true.




I'll probably just open them up when they show up and check. I can confirm the th-112 +2 -2 is not connected to anything internally 

Thanks everyone.


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