Woofer damage from new Star Wars THX DVD?


Both woofers in my JM Lab Utopias blew with the THX intro (exploding sphere) on the new Star Wars DVD. Happened at normal listening level through my Theta Casablanca II/VTL 7.5 preamp/Halcro dm58 amps. I've not blown a driver in over 30 years of being an audiophile. I've heard that the base was boosted as much as 36db on some of these DVDs. Even though the speakers are under warranty, I'm out $1,200 for a new Focal woofer (JM Lab only covers 1 driver for this kind of damage). Anybody with information or suggestions? Needless to say, I'm not happy about eating this expense if the fault really lies with an overmodulated DVD with no warning about increased bass levels. At the verey least, I'm curious to see if this happened to anyone else. The sound level was high enough that the concern for hearing loss came to mind (I'm a physician and I don't think I'm this concern is frivolous). Thanks for any thoughts or other input.
Ag insider logo xs@2xavimar
I would think that there would be little chance of "real world" setups being affected, simply because either most low end amplifiers don't have enough power to blow out a speaker like that, or the systems don't have enough bass extension to even attempt to reproduce uberbass like that. It's only gear that's good enough to try and powerful enough to fail spectacularly that causes problems . . . .
Hmmm....
A 36 dB increase from what level? There's gotta be a reference point somewhere, right? And the frequency(ies) of attenuation might be better info to provide also.

But quick advice would be to check the disc vs. another. I'm sure SOMEBODY else besides you bought it. Distortion, rather than dB level might also be the problem. Whether produced by source, software, or amplifier (gain stages, yep!), the distortion is much harder for the amplifier to control than a clean over-emphasized recording.

Threatening the speaker manufacturer with negative newsgroup postings might get you some sympathy. Or maybe organizing a petition if enough people have actually had damage occur, you could contact the disc manufacturer. Keep accurate records either way. I'm curious.
As with most software, I would assume that the manufacturer only warantees the product, NOT the aftermath. Or connected components.

Back to the 36 dB issue.... WHERE did you hear this?

And lastly, if the SPL was enough for you to consider hearing damage..... Maybe you have a class action lawsuit on your hands. George Lucas probably has some mighty deep pockets. Of course, he might counter-sue because your Utopias aren't THX-Ultra II rated. Nor was the amp or the cables.
Tsrart, your theories are largely incorrect for your reference. It really doesn't work that way. What happens is largely that drivers(usually the tweeters first) get blown from being UNDERPOWERED when asked to handle more demanding levels! The amp cannot supply the current to properly control the driver(s), and therefore "clips", causing the drivers to distort, to simplify.!
It's a common misconception amoung new audio enthusiests, to think that too much power is the cause of breaking speaker components. It's not the case largely.
Also, a speaker will only respond to the signal and current that it's being fed. If you have more expensive/higher out-put potential gear, the gear isn't going to "try harder" or drive harder per se, simply because they have more potential.
It's not like a race car engine that's "more tightly wound" or anything. We're just talking about passive components that are sometimes overpushed from what they can comfortable handle. Or they are underdriven from the volume they're being asked to handle. Talking about speakers of course.
Thanks for your comments, Sean; always helpful.

I went back and played the DVD again last night on my Mezzo Utopias (powered by a Belles 350A) and on my Paradigm 100s (Parasound 1500A) with and without VMPS sub (Crown K2). I played them both hellishly loud (paintings on the walls went crooked and stuff in the china cabinet rattled and danced around) and none of the woofers even bottomed, let alone blew.

Something pathological has to be going on with Avimar's system.

will
I did the same thing Will. I could not understand how that could damage ANY system, even at massive volume. I turned my pre / pro up seven notches higher than normal ( and i like it LOUD ) and nothing even flinched. There just isn't that much bass during the opening THX "electrified exploding sphere" sequence. Something is really wrong somewhere. To blow up a driver ( let alone two ) with that big of a motor structure would really take a lot of brute force over an extended period of time. Either the drivers themselves should have never been shipped out the door ( defective ) or the amp has got BIG, BIG problems. Sean
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