Chronic Cornwall midrange diaphragm failures

[atldan2010]

I have a pair of Cornwall II's and one has had a chronic problem with blowing midrange drivers. The speaker plays fine for a while but when I raise the volume the diaphragm blows. When I take apart the midrange driver the diaphragm is blown completely off the housing and the only thing holding it together is the pair of wires going into the diaphragm. I have already replaced two but something is wrong.

I was thinking maybe a faulty crossover is letting in too much voltage, or not regulating it properly, resulting in the blown diaphragm. The crossovers are new but maybe something is broken.

Any ideas on isolating or solving the problem would be appreciated.

Thanks....D

[Mike Dubay]

Pictures of the cross overs could help. You said new, where they DIY or did you purchase them?

Could there be too much low frequency signal going to the squawker? Do you have a multimeter that measures capatance? Check to see if you have a bad cap.

[djk]

Either wired wrong or defective.

[LarryC]

nm

[sebrof]

To isolate I would switch crossovers. I assume that you have one good diaphragm at this point. I would play that speaker loud, a little louder than it was when the other diaphragm blew - Test it to make sure it wasn't about to blow when the other one blew. Then I would put the crossover from the blown speaker in the good speaker and play as loud as it was when the other one blew (maybe a little louder just to be thorough). If it blows, it would point me to the crossover.

If it doesn't blow, I would connect that speaker to the same channel as the one that blew to start to isolate my amp, cables, etc.

Hope this helps

[ab0ez]

What amp are you running on your Corns? Sounds an awful lot like some clipping action going on there.

[PrestonTom]

Is this a stock crossover (and wired correctly) or have there been modifications?

[HarryO]

To isolate I would switch crossovers. I assume that you have one good diaphragm at this point. I would play that speaker loud, a little louder than it was when the other diaphragm blew - Test it to make sure it wasn't about to blow when the other one blew. Then I would put the crossover from the blown speaker in the good speaker and play as loud as it was when the other one blew (maybe a little louder just to be thorough). If it blows, it would point me to the crossover.

If it doesn't blow, I would connect that speaker to the same channel as the one that blew to start to isolate my amp, cables, etc.

Hope this helps

That's an expensive way to tell if you have a bad crossover. Diaphrams on ONE speaker should tell you you have an issue with the crossover/wiring.

I just had an issue with a binding post replacement being too long and dug into the circuit board causing tweeter diaphrams to blow.

Do a thorough inspection and comparison between crossovers. Make sure you have the mids wired properly identical to the good speaker.

If you can't pinpoint an issue from there you should probably send it to a qualified tech such as BEC or a couple of other forum members.