Problem with vintage speakers.

RedBull

Well, I was having a house party last night when out of nowhere I smell something burning. Being that all the stereo equipment was mine I immediately rushed over to the receiver and where everything is plugged in at. Nothing going on there, then I take a look over to one of my speakers and what do you know, the bloody thing is on fire. Literally on fire! I was so shocked. Theirs nothing near the speaker that would cause this, and after ripping the grill off and extinguishing that, I see that the cone is on fire. That took a while to get out, but my question is, has anybody heard of anything happening like this before? The speaker is done for, and I don't really mind too much, I had a backup pair to finish out the party with and they were free (pair of MTX AAL 1240). It was just wild to look over and see my speaker on fire. I would post a pic of the damage to the speaker, but being that it burned through about 35% of the cone, some of the party goers decided to have a little fun with the "trash"

EDIT: I should probably also ask if you guys have any ideas as to what may have caused this. I am using pretty old speaker wire, but my first assumption would be internal problems.

Schurkey

First Guess: Somebody put out a cigarette on your speaker cone.

Second Guess: Shorted voice-coil overheated the cone. Surprising that the receiver didn't shut down.

Third Guess: Spontaneous Speaker Combustion. Might want to keep a few fire extinguishers handy.

RedBull

Thanks for the guesses Schurkey. I'm pretty sure (actually just hoping) someone didn't put out their cigarette on my cone, because I didn't smell cigarette smoke, so I'm going to rule out that. Based upon what I saw, I think your second guess is probably correct. From the hole in the cone I could see two wires that look like they have melted through in the middle. Now that you mention it, I'm pretty surprised the receiver didn't shut down. Losing a speaker like that would have to have caused some funky stuff to be going on. Either way, it doesn't sound like the speaker wiring I used isnt at fault, but I think I'm going to go figure out where the fire extinguishers are at in the house, so that if something like this happens again I won't burn down my house...or ruin more gear.

inspiredsports

Wow, this is rare. I thought it was something that only happened in a movie.

Having fire extinguisher on hand during even my rare 110+db listening sessions is something I've never even considered.

I would suggest a careful inspection of the wiring and crossovers if you rebuild the bad speaker, as well as an inspection of the other in the pair.

How loud was the listening level?

TroyD

It was turned up to loud....the amp was WAY overdriven...sent DC to the speakers, they got hot caught on fire.

Solution? TURN THAT **** DOWN!

BDT

RedBull

The receiver was turned to -10. The receiver is a harman kardon 3490. The speakers say 200 watts, they are MTX AAl-1240. I don't believe turning it up too loud was the problem. It's been to +5 many times for extended periods of time before without a problem. I don't really plan on rebuilding the speaker though. I had a backup, and these were free. It just gives me an excuse now to go out and buy a decent pair.

TroyD

I'm just giving you a hard time...

That said though, the speaker rating has nothing to do with it. It can take 200wpc, what it can't take is DC from an over-driven amp.....your receiver was clipping and it fried your speakers. That's what happened....

BDT

skrol

Actually TroyD may have hit on something with the sending DC to the speakers. There are failure modes (ie shorted capacitor) in amplifiers that will result in excessive DC offset voltage at the speaker output and will fry a voice coil. Before you connect another speaker you might want to connect a good quality volt meter to check. This link has some info on checking the DC offset.


http://www.audiokarma.org/forums/showthread.php?t=5634

RedBull

Thanks for the info. I'll have to get a hand on a volt meter to check that out. I'm not too upset about the speaker, but if their is something wrong with my receiver then I'll be pretty upset considering it is less than a year old.

michaeljhsda2

Years ago just for grins, I had some cheap **** speakers that I hooked up to a Crown Power Base 2 amp. Curious to see what would happen when I really cranked them up....sparks, then a pop,then smoke came out. Burned those voice coils good. No damage to the Crown amp.

heiney9

Shorted voice coil or large amount of DC coming from your receiver. I had this happen to me in a high end retail store when I was demo'ing a pair of speaker for a customer. Poof smoke and flames.

Never did quite figure out waht happened............final guess was our speaker switching board (manual push button) must have shorted out.

H9

zingo

I've burned up tweeters before (literally) by over driving them; crappy speakers and a crappy amp cranked up is a bad combo. It happens to the best of us and just be glad it wasn't a good pair of speakers. This isn't necessarily a problem with vintage speakers, but age doesn't help the problem either. Glad everything turned out okay.

geppy1

Had that happen during a demo too. A little hard to explain to the customer while your putting out the fire.Keith

gdb

Always use Cerwin Vegas for an off the hook party!!;):D

RedBull

gdb wrote: »

Always use Cerwin Vegas for an off the hook party!!;):D

I'm thinking I'll be getting a pair of VE-12F's on the cheap for my next set. I haven't gone out and demoed to many speakers, but I'd rather not buy a nice pair when their primary purpose for a couple years will to be provide sound to a college house.

gdb

Bose 901s can really put out the decibels too, and they can be found for very little money nowadays.;)

smcgov34

that could be your speaker's way of telling you it doesn't really want to have to play Lady Ga Ga for a living!