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[George Holloway]

I am currently running a pair of peavey 18' subs with a qsc 2450 amp and found a static/noise coming out of one of the speakers. For fear of ruining the sub, I moved a couple of cables, but that didn't fix the problem ,so I brought in a spare Yamaha 118 sub that I had to finish off the show. It initially work fine for a while but then it happened...The Yamaha quit all together. Any thoughts to what could be going on.

By the way,, I'm a real noob when it comes to this kind of thing, so take it easy on me. I'm just the guitar player.

[Whit Hutchinson]

Bo,

How did the Yamaha sound when you hooked it up?  Did it have the same "Static" as the Peavey?

Which Peavey subs were you running and which amp were you using to run them?  It sounds like you may be burning up the drivers.

[George Holloway]

I was using 2 SP118x Peaveys, powered with a QSC2450 amp bridged mono. When I started to get the noise out of one of the subs, I swapped it out with a Yamaha CW118 and it sounded great for a while then quit working all together. I did a little troubleshooting last night and found the Yamaha completely blown(OPEN). The Peavey still works but it has a decaying staic sound.It still pushes lots of air but it sounds like its on its way out.

[Whit Hutchinson]

Bo,

It does not sound good from what you are saying.  It sounds like you cooked the Yamaha and the Peavey has gotten hot enough to warp the voice coil and its scraping in the "gap".  

Depending on the SP 118s that you have, you may be well over the threshold for power if you are continuously clipping the 2450.  You are sending a solid 1,200 watts per speaker in the current configuration.

1.  How often are the red clip lights coming on?
If Steadily, then you need to back WAY off.  

2.  You may want to consider replacing both of your Black Widow drivers to some more powerful drivers. Peavey offers stronger drivers but this will not fix your need for more bass.  If you find yourself clipping the amp constantly then you need more subs.  

For the time being I would suggest at least replacing the basket of your damaged Black Widow and watching the level very carefully since you are over the recommended power level for those speakers to start with, much less at full tilt from the amp.  Consider upgrading to higher powered drivers (I think the newest driver is the "Pro Rider" which holds more power than the older Black Widows).  If you swap out to upgraded drivers in both, you will still have a spare replacement to work with in case.

[George Holloway]

I have already ordered another speaker for the Peavey and I found a guy that needs my blown Yamaha. So with that.. I have another question. Would it be better to run 1 peavey per side with the QSC2450 or will it be enough?

[Phil LaDue]

You should be fine with 1 SP118X per amp.
I can't figure out why they are blowing up, you might want to have somebody meter the power you are using as a start.

[Whit Hutchinson]

Bo,

Running 1 118 per side off the 2450 will probably not be enough power unless they are 4ohm SP 118s.  If I remember correctly most are 8 ohm.

This is a tricky scenario that many of us have seen before.  Not enough power with 1 per side and potentially too much bridged.  You still did not answer how often the amp is showing a clipped condition from the indicators.

If you still need more bass I would recommend another SP 118 per side and then run 2 118s per side of the 2450.  They should be able to handle anything the 2450 can throw out in that configuration unless you push the amp into a constant clip state, then it would sound like shit anyway and should be very audible.

[Phil LaDue]

I interpreted side as L+R not amp channels.
1 per bridged amp gives you 1300 watts.
Not ideal, but it will get the job done.

[George Holloway]

I really didn't get to see how many times they were in the red. I asked a guy that was there and he said that they we're red quite often. Question: If the channel knobs are rolled back to 5 on the amp, does this mean I am sending out 50% of the power?
I don't understand how this stuff works, but I do know that I don't want to keep blowing up my gear. I do have some other power amps of lower power, but they are also of lower quality.

2ea. Nady 900
1ea. Nady 1100
1ea. Carvin (not sure of power rating)I think 1000 watts
1ea. Peavey CS800
2ea. Peavey 600
in addition to the QSC2450

Do you have any suggestions for using these?

[Phil LaDue]

If that Carvin is a DCM1500 give it a shot.

[Whit Hutchinson]

Bo,

Going to a smaller amp wont fix anything.  It may make it worse since you may push it harder trying to get the volume that you used to have with the larger amp.   The "volume" settings on the amp channel have NOTHING to do with how much power it puts out.  For instance, it can put out full power almost all the way down if you send it enough singnal.  Just like right now, you said you have it on "5" and you said that its clipping often.  This means that the amp is running its absolute maximum power with no headroom left.  These knobs are used to best match the signal you are sending the amp.   Right now I would suggest two options:

1.  Run the amp with one speaker per side (as you suggested) until you can learn where the limit is.
2.  Continue running the bridged setup but be VERY careful to keep the amplifier completely out of the red.

Learning can sometimes get expensive as you are seeing now.  Most everyone that has had to figure this stuff out on their own has blown up gear including myself (more than once).

[Phil LaDue]

I suggested trying another amp just to rule any other problems beside simply overdriving it.

[Ivan Beaver]

Why not just take the Peavey apart and LOOK at it?  That would be a good FIRST start, rather than playing around with amps.

It might just be a piece of trash in the gap.

You can learn a lot by looking at the voice coil.  On most loudspeakers you can't, but on the Peaveys and a couple of others, a couple of bolts and you are "in".

If it is burnt or other wise damaged, the actual damage would be nice to know, so as to help figure out if the problem is overpowering, or DC offset on the amp or oscillation etc.

THEN you can procede.  Othewise you are simply guessing.

Divde and conquer!  The number 1 rule of troubleshooting.  Guessing is the last resort.

[George Holloway]

I did take the affected speaker apart to check the coil, but didn't really see anything that stood out as damage. It looked smooth and didn't have any rub marks to speak of. (which doesn't mean that I didin't miss something)I also didn't find anything in the gap. I have already ordered another speaker, so at worst, I have a spare assembly.
I wasn't running the amp at 5%, I was just wondering if it worked that way. I ran that baby full on!!
So let me get this stright before I do it. It will be fine to run 2 Sp118x speakers (daisy chained) on a QSC2450 in bridged mono as long as I keep everything out of the red.

[Whit Hutchinson]

Bo,

In short: Yes.   Keep in mind,you are over the recomended "Program" power for Black Widows.  You will continue to BBQ these speakers if you do not watch the level.

You can experiment to see if one per side is enough and this will reduce the chances of tearing up the speakers again, but this does not mean you can run it constantly into the red either.


Other than that I would suggest playing a CD through your system with heavy bass content (rap or heavy rock).  

1.Turn on the amps and unplug the speakers from the amps.
2. Run the level up to the maximum output of the mixer (just before in the red.  Do not clip the mixer either).
3. Adjust the gain "volume knob(s)" on the amp(s) until the clip light flickers.  Reduce the gain a few more "clicks" down past this point (maybe 1/8th of a turn) so that the clip lights do not light AT ALL.  

The above steps is a very crude example of gain structure setting, which you may want to research a little bit.  But the above steps should keep you from blowing subs at every gig.

[George Holloway]

Thank you so much for the help. I know I've been a huge pain in the arse but I'm now trying to learn the craft and this is the best place to get good info. I'm quite sure that I will be in need of more advice in the future. Cheers to all Thanks again.

                                               Bo Holloway

[Al Limberg]

Fifteen posts and not a single question regarding the HPF setting on the RMX2450......hmmmm. The combination of regular clipping and a speaker cabinet tuned near 50hz seems like an entirely perfect time to dig out a mini screw driver and flip those dip switches!

JMHO,

Al

edit
p.s.  Nobody has bothered to ask if a newbie might be adding 15db of boost on his graphic at 20hz going for that'round sound' as well.

[Whit Hutchinson]

Oh yeah, what Al said too.  

[Tony Martin]

I'm a bit hung up on the description of the noise as "static".
By this, did you mean a crackle and pop kind of thing when the system was at rest, or more of a "grinding" kind of noise only when the speaker was being driven???
If it is indeed the latter, which seems to be the popular assumption here, it could be something as simple as a dust cap on one of the drivers coming partially un-glued. Could also be a surround or spider starting to let go.
Someone already suggested taking the cabinet apart and looking at the speakers. Be aware when you do that the dust caps often LOOK okay when sitting at rest. You gotta move them a bit to tell if they're coming unglued. Likewise the surround. It could be separating from the cone and you'd have to look quite closely to notice.
Hopefully it's one of these problems as they can be fixed easily, and a lot less expensively than reconing or replacing drivers.
Good luck with those.

[Whit Hutchinson]

Tony,

It could be many other things including:

1. Dust Cap (as you said)
2. Tensile leads touching the cone.
3. Torn Surround  

We can assume its not the amp since switching speakers worked and the other subs did not "have static" even though he managed to blow the Yammy.

I did not mention the above items since he said he has already bought a new driver/basket.  In any scenario a 2450 at  full power > 50% of the time is more than Black Widows can handle so I figured this was the most important item to address.

[Tony Martin]

Whit: Thanks for the reply.
I agree with all of what was pointed out by the various members who have posted to this thread.
But over the years I have also learned that sometimes we look for the tough answers when the solution is actually something easy.
I'm, sure at some point in all our lives we've had a problem which we've immediately started dissecting, looking at wiring, or component failure, only to find someone had turned down the input gain on the amps or had switched off the power on the crossover, or something equally silly and simple.
I simply addressed those "simple" things which had not been touched on here in the hopes (for the Op's sake) that the solution may be something quick, easy and cheap which had been previously overlooked.

[Douglas R. Allen]

Tony Martin wrote on Sat, 20 October 2007 11:07

Whit: Thanks for the reply. I agree with all of what was pointed out by the various members who have posted to this thread. But over the years I have also learned that sometimes we look for the tough answers when the solution is actually something easy. I'm, sure at some point in all our lives we've had a problem which we've immediately started dissecting, looking at wiring, or component failure, only to find someone had turned down the input gain on the amps or had switched off the power on the crossover, or something equally silly and simple. I simply addressed those "simple" things which had not been touched on here in the hopes (for the Op's sake) that the solution may be something quick, easy and cheap which had been previously overlooked.

When you played your sub at a low level did you hear this crackle sound? Why I say this is because it doesn't take much of a rub to sound bad. Many times I have just marked the "magnet bolt hole to speaker basket" alignment with a marker. Removed the bolts and turned the magnet 1/3rd a turn and put the bolts back in and the rubbing sound stopped. Some times you can spin the magnet and find one spot that doesn't rub. The voice coils get pretty hot and may cool down somewhat egg shaped to a small degree. Also there is a very small left to right and up to down play in these. Sometimes you can just push the magnet to the Left or Right or up and down while tighten the bolts and stop this rubbing. When you just set the magnet on the basket reach under and GENTLY push on the cone. If you hear any rubbing give the magnet a 1/3 of a turn and try again. I had one stubborn speaker that I ended up only using 2 bolts because with 3 it rubbed no mater what I did. The person I sold it to says its still working fine 9 years later. Play around with it. You may have a good speaker basket. Or at the very least a good spare.

Kindest Regards
Douglas R. Allen

[Scott Shaw]

Check the foam filter on the magnet to make sure it hasn't deteriorated and fallen into the gap. It has a tendency to dry rot over time. If it did, You'll find a black goo in the gap, on the coil, and behind the dust cover. Another thing to check is the spyder. Sometimes a section will work loose and cause a crackling sound. Super glue and a few clamps will fix that.

Scott

[Kevin wiacek]

I've done the same exact thing, I've blow mine twice now (sp118x-8ohm).......except I put around 1000 watts threw each, I also tried running them at 800 watts each......Now I run them with the same amp you have but one sub per Chanel 500 watts each and its perfect. Peavey has a really screwed up way of rating their speakers, what they told me to do for thees subs was to run 450-550 watts into them and to a 40 hertz roll off.

So running them at 500wats(QSC 2450 one sub per channel) with a 40 hertz roll off works mint.