What happens to speakers when they burn out?

[Electricblue]

I have some scrap drivers laying about that make a kickass sound when i put too much power into them (fuzzy) i know this will destroy them. but when they burn up, does the impedance drop to 0 ohms or Infinite ohms? I dont want to mess up my amp when they eventually die.

[Rockman]

Originally Posted by Electricblue

I have some scrap drivers laying about that make a kickass sound when i put too much power into them (fuzzy) i know this will destroy them. but when they burn up, does the impedance drop to 0 ohms or Infinite ohms? I dont want to mess up my amp when they eventually die.

Uh neither of those are what happens, that would be an electrical failure. When a speaker fails its usually a mechanical problem. For example infinity ohm is basically not having the circuit complete, as in nothing plugged into the output, 0 would be if you just took a wire and ran it from + to -, which would be an excellent way to cause a spark show and start a fire.

[Electricblue]

Originally Posted by Rockman

Uh neither of those are what happens, that would be an electrical failure. When a speaker fails its usually a mechanical problem. For example infinity ohm is basically not having the circuit complete, as in nothing plugged into the output, 0 would be if you just took a wire and ran it from + to -, which would be an excellent way to cause a spark show and start a fire.

Yah, if it was electrical fault, would it turn into a straight short?

[Sneakypete]

No-one can say with any certainty what would happen with a faulty driver that is being severely overloaded. The coil could get hotter and hotter so that the varnish which it relies on for insulation melts resulting in partially-shorted turns in the coil which bring the impedance below the lower limit of the output stage of your head. In decades of playing I've only ever had one truly faulty driver - a 15" in a cab that I bought as "not working - no sound" . It turned out the cone was completely seized up - no movement whatsoever. I replaced the driver and got a good cab really cheap.

[gregoire1]

I have intentionally overdriven two speakers to failure. At first they did what your describing, sounded like "soft fuzz" (neither speaker was in a cabinet). after a few minutes you could smell the voice coil cooking. Eventually, the "fuzz" increased till the sound stopped and the speaker fell silent, followed by a final whisp of smoke.

One of the speakers acually caught on fire, but it was a very small speaker, less then 3 inches. The other speaker was a 12 incher, which just stopped working. A post-failure examination revealed both voice coils burned open (not shorted), the cones were otherwise fine (except for the fire of course).

[Jeff Scott]

Do they go to speaker heaven?

[T-Bird]

Hi.

There's no way of telling what happens.

That said, IME the usual damage for the voice coil in an overload situation is an open connection, which is pretty safe for an SS amp, but usually burns up the tube amp OT.

Regards
Sam

[BluesBear]

It depends on HOW the speaker fails. If it's a simple matter of too much current then the voice coil usually melts like a fuse and you end up with an open circuit and no electrial path.

If the failure is due to excess cone excursion from high transients where the voice coil tips and locks in position it can short across the flux gap and you have a zero-ohm/short circuit condition.

[Electricblue]

:S i should probably get a fuzz pedal or something then. Or tear some holes in a driver. Cheers guys.