Blown Pa? Blown Speakers?

Volitions Advocate

Volitions Advocate

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900 Watt Crate Poweramp. 450 a side in bridge mode. 2 300 Watt speakers on each side. Peavey "PV8" mixer.
Playing all night. same volume we've been playing at all week with this setup.  Our bass player's Bass cabinet developed a rattle so it has been in the shop.  So we hooked his amp head up to the mixing board with the DI out on his head.  Playing our last song of the night and the speakers stopped working.  No smoke, no smells.  Power amp seems fine. it seems unlikely we would've hurt it.

Volume out of the speakers is nearly completely gone.  Theres 3 tweeters. 1 horn and a 12" speaker in each, and the only sound is coming out of the tweeters and horn.  the 12" speaker doesn' t even have static.

We pulled the back plate off to chekc the solder connections, theyre' all intact.  Although theres a weird little rectangular box attached to the cables soldered to the input jack that looks like it might be a fuse.  The coil on the back of the speaker is really really hot.

  It doen'st look like we've "blown" anything.. at least not physically.  Everything was going smoothly all night.  No distortion out of the speakers or any thing.  I think the bass just pushed it too hard.  Do speakers just "shut off" if they get too hot?  Will waiting for them to cool down be a viable hope to hold on to?

I had kind of a crappy day and this just pounded the nails in the coffin.
 
Try plugging a mike or instrument directly into each channel of the power amps inputs; if you get volume out of each channel, your mixer's gone, if not, the power amp is blown.
 
Don't forget to check all of the fuses, I have a friend that has a cantankerous bass amp that seems to like to blow fuses.  Whether it is because he is a metal head and plays with an overly hot signal or because the amp has more issues than he knows about, the bottom line is that the fuses go rather frequently.
Patrick

 
we hooked the bass amp directly up to one of the speaker cabinets just to check and had the same results.
I dont think the problem is in the amp.
 
I'd pull the 12" driver and check the impedance of the voice coil with a multi-meter.  If it reads a really high impedance, you've blown the voice coils in those drivers and a re-cone or replacement is in order.

If the driver checks out to have less than 10 ohms, then it's either the crossover, or the mysterious black rectangle box.  Again, check it with your multi-meter to see where the fault is .  Once you know where it is, it should be easy to fix.

BTW, what brand are these speakers?  If they're yorkville and less than two years old, there is an "even if you break it" warranty on them.

Finally, I'm assuming that your monitors were fine through all of this - is that right?
 
never had monitors set up. just these 2 speakers.

The pair of speakers were a boxing day purchase of 100 dollars for the pair, and theres a big "Z" marked across the cone.  They were pitched as "DJ speakers"

Cheap, but they worked. the problem being money to find a replacement seeing as how they were borrowed.
 
It is generally a bad idea to use speakers for amplifying instruments if they were not designed for it. It gets worse if you push them to higher levels for longer periods. The reason is mainly that when used for instrument amplification (and this is especially the case with bass) you will be sending a more constantly high signal through them than if you just send 'genreric music' into them as would be the case in a 'dj' application. Speakers for instrument amplification have much larger voice coils designed for high heat dissipation. Your speakers very probably were not able to get rid of the heat and shorted out. There's one element of hope and that is that the mystery black box may be a thermic protection which cut the circuit before the speakers were fried, but then I would expect it to reset as the speaker cooled again.
 
well the little box is about 1 1/2 inches long and less than a half inch in the other 2 dimensions.  And its actually white, not black.  I can't remember what it said on it. I'll check later today.
 
While you're at it, make a sketch of how everything is wired together: the external connector, the speakers, the little box, anything else that may be in there.
As a quick check to know if it's the speakers that are dead, you can touch a 1.5 volt battery across the speaker terminals. Just use a light touch to draw it over them (you'll probably have to use a wire on one pole of the battery). If the speaker is OK you should hear some crackling sound. Of course, using a multimeter as mayfly suggested is a better way but you may not have one available.
 
DJ speakers with Piezoi's and the like...probably fried those 12's.  Running the bass through the PA probably did it.  Also I'd question the power handling of those speakers.  You say 300 watts...I'm guessing that's peak power, and the amp was just too much for them along with the bass guitar signal.  Multi-meter or 9-volt battery across the terminals on the 12" will tell you.  I've seen many a cabinet blown by ignorant DJ's.  It's all about gain structure.  How much juice was the board feeding the amp?  With those speakers, I'd keep the master output from the board at or below -3db, and make sure none of the channel strips are clipping.  Sounds like those speakers just weren't up to the task.  Pick up some cheap Yamaha Clubs or similar and you should be fine.  I wouldn't trust those "DJ" cabs.
 
sorry. 2 speakers. 1 on each side.
Funny thing was nothing was clipping. and it wasn't up that loud.  It actually sounded really good, first time we got the sound through it "right"
 
Volitions Advocate said:
Verdict is in. Its the Woofers. I need replacements.  Where do I go to get dirt cheap 12 inch pa speakers?
Click to expand...

Define "dirt cheap"? I would think the "900watt bridged/450watt stereo rating is probably quite bogus and into 2 ohms, but that poweramp isn't apparently being made any more and I can't find specs on it. Figuring you maybe have something like 200 real watts a side, "dirt cheap" 12" PA speakers most likely aren't going to last you a real long time, especially if you're blowing heavy bass frequencies through them...

Here's an $80 speaker that's rated for your application if your cabs are ported/vented, anything cheaper, you're wasting your money:

http://www.partsexpress.com/pe/showdetl.cfm?&User_ID=49665988&St=4462&St2=-56175012&St3=84131992&DS_ID=3&Product_ID=7590&DID=7

If your cabs are SEALED you need to use a better speaker, run you $95 dollar each:

http://www.partsexpress.com/pe/showdetl.cfm?&User_ID=49665988&St=4462&St2=-56175012&St3=84131992&DS_ID=3&Product_ID=7592&DID=7

Partsexpress.com a great source if they carry the speakers you want and will typically ship same day as long as you call them early. If you go looking on their site stay AWAY from the $50 PylePro/Pioneer speakers, you will just blow them up, too, using that PA amp....
 
The idea is to replace the speakers (since they'r enot mine) and not use them anymore. because they're too cheap.  Theres no point in investing in a couple of 200 dollar speakers to put in these crappy enclosures.
 
Volitions Advocate said:
The idea is to replace the speakers (since they'r enot mine) and not use them anymore. because they're too cheap.  Theres no point in investing in a couple of 200 dollar speakers to put in these crappy enclosures.
Click to expand...

I was suggesting $80-95 dollar speakers, not $200 ones? Go ahead and buy the $50 dollar ones, just don't come back crying when those blow up, too...
 
jackthehack said:
Volitions Advocate said:
The idea is to replace the speakers (since they'r enot mine) and not use them anymore. because they're too cheap.  Theres no point in investing in a couple of 200 dollar speakers to put in these crappy enclosures.
Click to expand...

I was suggesting $80-95 dollar speakers, not $200 ones? Go ahead and buy the $50 dollar ones, just don't come back crying when those blow up, too...
Click to expand...

Jeez, just get the darn Emi's like Jack suggested.  Anything cheaper, and you're wasting you time and looking to blow another set.  You can't get much more bottom shelf than that.  PA cabs need to take a beating, and you seem unwilling to realize that and put the right drivers in there for that application.  Reminds me of a chaep a*** dancer bar manager I know.  She refuses to take any of my advice and the dancers keep messing with the board and blowin stuff up.  As the saying goes, you can pay me now, or pay me later.  Just do it right for crying out loud.
 
Holy crap guys, it's not like i'm looking for a fight here.

Jack the reason I said I wasn't going to use 200 dollar speakers is because Its what I saw all around town today, not because I was exaggerating on what you suggested.  I'm thankful for your suggestion.

and I did say I was going to fix the speakers and give them back to who owns them and not use them anymore.  which means I'm NOT going to blow any more speakers, The owners play bluegrass and all they're going to do is hook them up to a condensor mic and pluck their mandolins.

Sorry if you guys took anything I said as rude or dismissive. It's not how I meant it.
 
Would it be an option to just get another pair of DJ cabinets for around $100? It might actually be cheaper than replacing just the speakers...
 
Well it was a boxing day sale item so I'm not really sure.  I've been to all the stores that sell that kind of thing and nobody has 'em.
I've emailed the guy that always does our sound at shows, he always has parts coming in to do work for people. He's already making some cables for me so I'm sure he has connections.  Barring that I'm probably just going to go with the site Jack suggested.
 
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