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Lonman, or anyone else in the know:

I was DJing last Friday and had both my powered JBL JRX118S subs running the exact same way. I had them piggybacking off of my JBL JRX125s. Meaning, I used my Crown XTi 4000 amp to power the mains, and just ran a quarter inch to XLR from the mains to the subs. Well, Friday, I'm not sure how, because I wasn't pushing the system hard at all, but I blew one of the subs.

Now, for reference, I had bought one sub more than a year ago, and bought the exact same one a few months back for extra oomph. The new one is the one that blew. I actually had it turned down slightly softer than the other sub because it seemed to be peaking a little harder. I constantly watch my levels to make sure nothing peaks for more than a half second, and even though it never did, I suddenly noticed a bad buzz in the music and traced it to the sub which had seemingly blown.

So, what did I do wrong? I've run the older sub this way for more than a year and never had a problem. This was maybe the third or fourth time I'd added in the second sub.

I admit, I don't know a tremendous amount about sound. I know how to make it sound like concert quality, but when you start talking ohms and such, I'm at a loss.

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hi-voxentertainment

I can save some time --- You ate using as your mains (2) 15" dual dual speakers with an internal crossover - Highs Mids and Lows go to the 2nd 15" - speaker is rated at 4ohms. Your sub is also rated at 4ohms - which when daisy chained makes a 2ohm load ( if I learned correctly ? ...Lon?)

It seems you amp can handle that but it seems to this ignorant KJ that you are trying to do too much with this set up. Don't know but hope you get a answer from the EXPERTS . Good Luck

Can you give a block diagram? It sounds like you said you were coming out of the Crown to the speaker tops and then to the powered sub, but that can't be right. If you are sending the output of the Crown to the powered sub, I could see how that would easily blow it. But I suspect I just misunderstood you.

It should be from the mixer, to the powered sub, *then* to the Crown and the main speakers. RIght?

Ok firstly, the JRX118S is not a powered sub.
Now HOW are you connecting these. 2 speakers PER side/channel?
The Sub is rated for 700 watts at 4 ohms. The 125's are rated for 1000 watts at 4 ohms. When you tie these together your amp has a 2 ohm load. Now at a 2 ohm load, they would require an amp that pushes 3400 watts per channel INTO 2 ohms. The Crown amp only pushes 1600 watts into 2 ohms, which is grossly underpowering this system.
Another major factor is the subs do not have a crossover built in. You are essentially sending them a full range signal which they are not designed to handle. STRONG recommendation would be to get a separate amp for the subs. The XTi4000 is a perfect mate for the 125's. A good match up for the subs would be the XTi2000 if you want to stay in the same line. Now I believe these amps have built in crossovers (or low & high pass filters at least) which you would need to set for the sub & your main top cabinets.
I know confusing, however, this system is completely set up wrong & you could even continue further damage to the drivers & possibly the amps.



This would be the reason, you were probably running it, if EVER you see those clip lights, that is distortion going to the speakers - big killer. Being this system is set up completely wrong, the subs are really power starved & were trying to rob power from the main cabs, on top of not being crossed over they were trying to reproduce frequencies they are not designed to reproduce.




Again how EXACTLY are you hooking up the system.



Ohms & such are huge things to know especially if you are going to be running sound.

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LIKE Lonman on Facebook - Lonman Productions Karaoke & my main site via my profile!

I used to run the single sub from the sub channel on a passive Behringer mixer, which is why I figured daisy chaining would be okay here.

Here's how I run the current system:

B-52 Prodigy FX (console)
2 XLRs out to the Crown XTi4000 (yes, it has an internal crossover)
2 speak ons (one per channel) out from the Crown to the mains
1/4" to XLR per main to sub

I have the high pass filter on the subs on, since the bottom 15 on those JRX125s handles the bass load already. When I have it off, it's bass overkill.

The sound coming from this system is pretty awesome, but if I'm not connecting it right, I need to fix it ASAP.

Somebody draw me a diagram? Before I blow out the whole stinkin' thing!

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hi-voxentertainment

You know, the more I look at the product listing for my subs on Guitar Center's site, I see there's nothing that lists them as powered. I know I'm sometimes pretty clueless about things, but feel like a tool here. I was told by the salesman at GC BOTH TIMES that they were powered, and was given suggestions on how to set them up. Methinks someone at GC barely knew more than I did...

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hi-voxentertainment

A powered sub (or any speaker) usually refers to the fact that they have their own inbuilt amp. So, unless they are a battery-powered sub (highly unlikely), then they would have to have both a signal cable and a power supply cable connection.

Ok maybe you have the JRX118SP.
You are going from the 1/4" on the 215 running to the sub???? WHOA!!! You can't send a powered signal to a line level (XLR) input without damaging the system - i'm surprised you haven't blown anything as of yet.
Now if that is the model you are using you could use a 1/4" to 1/4" as the subs have a speaker level input - however this is not really recommended & you would still be MUCH better off just getting an external crossover. This way you can run the outputs of the mixer to the crossover, the full range outputs to the Crown/JBL 215 combo & the Sub outputs to the powered subs. Doing this would give you much better control & overall sound quality.

Until you get a crossover, you should run the system this way!
1. Mixer to the XLR inputs on the sub - channel A if using two subs!
2. Set the sub HPF (high pass filter) on.
3. Run the Channel A Output XLR to the Crown input channel A.
4. Connect 1 JRX215 to Crown amp channel A output.

Repeat for 2nd set of speakers using channel B in's/out's.

If ONLY using 1 sub. Run both outputs from mixer to sub input A & B.
Set to HPF on.
Run XLR outputs on the sub to Crown amp inputs A & B.
Run JRX215 from Crown Amp - 1 speaker per channel as normal.



It should sound awesomer (a word?) now!

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LIKE Lonman on Facebook - Lonman Productions Karaoke & my main site via my profile!

GC rarely knows what they are talking about. I know several people that work there .

Can you snap a pic of the back of the sub where the ins/outs are and post up?

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LIKE Lonman on Facebook - Lonman Productions Karaoke & my main site via my profile!

I'll snap a pic and post it up sometime today (Saturday) for you, Lonman. Your knowledge is much appreciated, so I want to see what you have to say before I move forward.

I just ran the one sub daisy chained off its main tonight. I was going to hold off altogether tonight based on the recommendations here, but I tried it at first, and there just wasn't enough boom. 'Bout half way through, I went 1/4" to XLR from one main into a sub. It gave me enough to get through the night, but I'm definitely gonna try some of what I've seen here before I hook up the system again (tonight, for a Sweet 16 party).

Thanks, guys!



~S

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hi-voxentertainment

Checked the backs and yeah, I supplied the wrong info. They are indeed the JRX118SPs. I'd send you to GC's site to show you a pic of the back, but it's not working right now.

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hi-voxentertainment

If you did a 1/4" cable to the "Speaker Level In" plug, that should work. But don't use the XLR! That is supposed to be a line level signal, I think.

I would think you would go:

Mixer Mono Out --> JBL JRX118SP XLR Input A, out OUTPUT A --> Crown Amp --> Mains

That way the crossover in the JRX118SP should pass only the higher freq signal to the Crown.

Then as I laid out before & mcky confirmed - except he forgot to mention enabling the HPF on the outputs FROM the sub.

For 2 subs running
1. Mixer Left output to the XLR inputs on the sub - channel A!
2. Set the sub HPF (high pass filter) on.
3. Run the Channel A Output XLR to the Crown input channel A.
4. Connect 1 JRX215 to Crown amp channel A output.

Repeat for 2nd set of speakers using mixer Right output & channel B in's/out's.

If ONLY using 1 sub.
Run both outputs from mixer to sub input A & B.
Set to HPF on.
Run XLR outputs on the sub to Crown amp inputs A & B.
Run JRX215 from Crown Amp - 1 speaker per channel as normal.

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LIKE Lonman on Facebook - Lonman Productions Karaoke & my main site via my profile!

Wow, see, I'd never have thought to do it that way. I have a Sweet 16 party tonight. Wasn't planning to use subs, but depending on where I'm setting up, I might go ahead, just so I can test this set up.

Thanks for the help, guys! I'll keep you up to date.

Now I just have to get in touch with JBL and get the warranty process going.

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hi-voxentertainment

Better make sure nobody from JBL sees this thread if you're gonna try claiming warranty for improper connection!

that's funny!

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LIKE Lonman on Facebook - Lonman Productions Karaoke & my main site via my profile!

Hey Lonman,

Real quick, I just realized I don't have a sub outputs on my Prodigy FX. I plan to use one sub tonight, so I'm wondering what to do. I do have booth outs, though, but they're RCA outs. How do I make this work?

I'm looking at the manual that came with the sub and it suggests going 1/4 to 1/4 from the passive speaker into the sub, similar to what I did.

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hi-voxentertainment

Like I said you describe the subs like they are passive, but yet your model number & GC said they are active. You do not need sub outs on the mixer, the sub has a built in crossover that will send the sub frequencies to the sub & the rest of the full range output to the input of the Crown amp to power the dual 15".
Is this what the back of the sub looks like? If so the way I described it is how you want to hook it up.

If ONLY using 1 sub.
Run both XLR outputs from mixer to sub input A & B.
Set the HPF on.
Run XLR outputs on the sub to Crown amp inputs A & B.
Run JRX215 from Crown Amp - 1 speaker per channel as normal.

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LIKE Lonman on Facebook - Lonman Productions Karaoke & my main site via my profile!

Yeah, I mentioned that I do indeed have the active sub.

Okay, I was misunderstanding you. Now I get it. I run the XLRs from the main outs on the mixer to the sub, then from the sub to the amp, then run the normal speak ons to my mains. Cool. I'll give it a whirl tonight and let you know how it goes.

Thanks, Lonman.

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hi-voxentertainment

Just wanted to check back in to say everything worked like a charm. Felt like I didn't have as much power, but still got plenty out of the rig to put on a good show.

Thanks!

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hi-voxentertainment