Well - my speakers caught fire.

[Mark Reccord]

Oh man, this thread delivers.

@killjeats: While I'm sure you're not particularly happy about having destroyed a couple of your speakers at least you have an awesome story to tell about it! Not everyone can say that they've literally caught speakers on fire.

I have seen this happen before in a JBL 4770 cabinet. We determined that what happened was after a history of being abused, the voice coil former on the driver warped enough that the VC scraped on the magnet which eventually shorted out part of the VC. In this case, the short in the coil caused the amp to thermal out but not before it created enough heat to set the glue and paper on fire. You could have fried an egg on the top cover of the QSC mx1500 and smoke was just billowing out of the cabinet.

It was a very rock and roll moment.

I also saw a 96kW lighting dimmer rack explode and burst into flames once. That was kinda scary.

 

[troy mcclure]

it was a smokin set... I have destroyed a voice coil and ripped a cone but never set a dust cover on fire...

 

[Passinwind]

Oh man, this thread delivers.

I have seen this happen before in a JBL 4770 cabinet. We determined that what happened was after a history of being abused, the voice coil former on the driver warped enough that the VC scraped on the magnet which eventually shorted out part of the VC. In this case, the short in the coil caused the amp to thermal out but not before it created enough heat to set the glue and paper on fire. You could have fried an egg on the top cover of the QSC mx1500 and smoke was just billowing out of the cabinet.

I am just a humble toaster tech. See, it says so right under my avatar. I'm serious about my toasters though and I think this is ultimately gonna be a job for Mythbusters. Who's with me?

 

[BurningSkies]

I am just a humble toaster tech. See, it says so right under my avatar. I'm serious about my toasters though and I think this is ultimately gonna be a job for Mythbusters. Who's with me?

This all makes sense to me now. @Mark Reccord is obviously a fried egg tech. We now have achieved breakfast.

 

[Passinwind]

This all makes sense to me now. @Mark Reccord is obviously a fried egg tech. We now have achieved breakfast.

Not until beans-on-toast brings the poutine. I hear he's a smokin' basket fry tech.

 

[BurningSkies]

Not until beans-on-toast brings the poutine. I hear he's a smokin' basket fry tech.

If you can get the OP to light up a cab, we could do it by campfire...it's a lovely day out here.

 

[Passinwind]

If you can get the OP to light up a cab, we could do it by campfire...it's a lovely day out here.

"Chestnuts roasting on SWR...
Jack Frost nipping at my Bose..."

 

[GreatScott91]

Now we know the best speakers for metal. Thanks!

True, but what is the best flaming speaker for metal???

 

[fretter]

I used to run a Peavey Mark VI through two EV 15" cabs. Eventually, I added a Marshall 2x10 cab with a tweeter. One day at rehearsal, an electrical spark-looking flame shot out of the Marshall cab, I think out of the tweeter. The rehearsal space was in an old house and the place's wiring might have been dodgy, who knows. The rig sounded great that day though

 

[beans-on-toast]

Not until beans-on-toast brings the poutine. I hear he's a smokin' basket fry tech.

This all makes sense to me now. @Mark Reccord is obviously a fried egg tech. We now have achieved breakfast.

Everyone knows that toasters make a great dummy load and that frying an egg on top of a transformer is the best way to determine if it's running too hot. I gave up on PCB transformer oil for frying.

Kumbaya.

 

[elkkid2]

That Speaker kinda looks like it's been re-coned. Was it? And, I've seen quite a few blown PAS Speakers that came from SWR Products. --Just sayin'!

 

[Mark Reccord]

If you can get the OP to light up a cab, we could do it by campfire...it's a lovely day out here.

Everyone knows that toasters make a great dummy load and that frying an egg on top of a transformer is the best way to determine if it is running too hot. I gave up on PCB transformer oil for frying.

Kumbaya.

I'm not doing anything until I've had breakfast.

 

[tedious1]

Everything else is a pissing contest or he said she said.

So throw in the obligatory "Burst P-bass, tort pg, and flats" and it's just par for the course on TB then...

EDIT: LOL and how apt is the siggy for this thread...

 

[AltGrendel]

Pedals can compress the signal raising the average power that the amp sends to the speaker. That doesn't cause flames, but it can cause the speaker to heat up more and not cool off as quickly as it may in a normal situation. Depending upon how many layers of pedals he's using that could be layers of compression and distortion...which could certainly cause speakers to overheat. As pointed out some speakers appear to be weakened anyway, in which case that thermal meltdown could do this.

I don't do audio per se(do not have the ears for it), I normally run lights. Would this be what gain structure is all about?

 

[timmerz]

I was in the room back in 1976(?) when a buddy of mine ran a 200-watt Marshall head into a Casino(sp?) cabinet (4x12) and halfway through the first song smoke and then quickly after flames erupted from the front of the cab (back was sealed)...

 

[BurningSkies]

"Chestnuts roasting on SWR..."

I don't do audio per se(do not have the ears for it), I normally run lights. Would this be what gain structure is all about?

Gain structure may have something to do with some of the confusion that people have as to whether a pedal can toast a cab. But what I'm talking about is how compression works (and not just from a pedal but from many sound altering devices). It not only brings down high volume peaks in signal, but it also raises low volume to a higher level. That's what I'm saying when I refer to a raising the average power your speaker sees. with uncompressed signal you may have spikes in the upper volume ranges but you have lots of dips and lows. The RMS calculation sort of accounts for how we send sound to speakers in that way... those 'rests' between the peaks give your speakers time to cool during your performance. Now if you're using or getting a lot of 'make up gain' you're bringing up the overall volume of the low stuff, so it's louder, your speakers aren't getting the same cooling that they might with otherwise uncompressed tone. While you've crunched down those high power peaks you're actually sending more power on average to the speaker... Would that kill healthy speakers? Probably not. But not everyone knows how healthy their speakers are.

Now we're talking about loud volume playing we may also need to consider power compression within the coil, something else that can kill speakers. Then while everyone's on about how pedals can start fires, we haven't even discussed how tone settings (heavily boosted lows, subharmonic pedals, etc.) could also make a mess of things. Just because it only has a 9v battery doesn't mean that it won't make trouble...especially once it rides through a handful of amplification stages.

 

[Munjibunga]

By the end there was smoke BILLOWING out of my 4x10 and probably the worst smell that I've ever smelled.

COOL!

 

[Bob Lee (QSC)]

You are seriously under-powering your cabs. The likely culprit is a clipped signal (to the point of DC) overheating the coils.

A clipped signal is not DC.

You must be joking about the "under-powering."

 

[Bob Lee (QSC)]

I have seen amps blow in a way that half the output was shorted and half was still working (or other weirder power stage failures). You can see a DC voltage AND signal, so it would make sound and fry the speaker at the same time. It's unusual, but it can happen.

That would be one mightily poor amp design!

 

[Bob Lee (QSC)]

Far too much of coupling C's in the system chain that block any DC,
at least at OT there is zero DC, sorry, pardon, did I mentioned that EVERY power amp input blocks DC?

There have been a few that don't.

I remember there was even sort of a "DC-coupled amp" fad back in about the 80's. For those who valued oddball specs over wisdom.