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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.
avimar

Showing 5 responses by spluta

spluta
58 posts
 
Avimar..

Sorry about your wolfers that really sucks.
I would raise hell with company over that...
Please do and let us know.. Maybe we all can
help you in some way?

I just tried that DVD (my sons favorite) I
measured with my SPL meter. I set my system
to a pretty high level and tested with an agressive
DVD-A first and was coming in at 100db max.
Then i left volume at same point and ran the
THX intro. I didnt see a jump in DB's but i
can tell you my Velodyne is pretty taxed on that
part. Im guessing its not the DB's that got you
but the fact that that intro hits some pretty
low freq's. Im crossed over at 90 for movies...
works well with my setup.

Its not a party till something gets broke!
spluta
58 posts
 
Slartibartfast..

Thanks for input.. I am somewhat new to PROPER
system setup and appreciate any and all advice.

Isnt the test pattern different for each PRE/PRO
.. louder/quiter?

When i use the test pattern on my pre and turn up
volume to where my speakers are before being stressed
im right at 75db's for all. This equates to about 100db's
consistent when im in two channel for a busy redbook. 105db's for DVD-A and upwards toward 110 for movie peaks.

Is this because my speakers are small and room is fairly
large or is it a setup problem. Should i be using something
besides Pre test pattern?
spluta
58 posts
 
Im saying my SPL meter is reading 75db's for all
7 speakers when i have the volume set to a high
level... the same level that produces 100db two
channel and ect... The test pattern is not as loud
as a real source cd, dvd ect..

The test pattern goes around in a circle and i adjust
level for speakers one by one to achieve proper level.
I believe it has nothing to do with how loud it is
for the test signal. Just that all of them match up.
So what im saying is all 7 speakers are set to the
same output levels. Is this right?

My speakers dont start showing stress until 100db's
with normal source material. I think there doing well
for size..

I dont listen at those levels for any prolonged period of time.. And i certainly dont watch movies like that..
I have a little bit of hearing left and im trying to hold on to it. (lots of loud gigs... Ive played electric guitar most of my life).
spluta
58 posts
 
Sean... is it possible for the drivers to blow
if they are sent a signal that is simply below their
achievable level? So this could be a problem caused
by a PRE/PRO capable of sending a signal below 20hz
and the speakers not being capable. I know in some
of the newer PRE/PROS you have an option of declaring
a sub as either THX or non-THX. And if you do declare
your SUB or MAINS as being THX a lower signal will be
passed. I remember reading about this problem somewhere
a while back...

I also played THX intro on mine and think unless he had
the volume UP WAY TO HIGH this shoulent have happened.
spluta
58 posts
 
Ok thanks Sean... You know I have an old pair of Fisher (flame thrower) three ways in my band room... Perfect
canidates for the EXtreme FLOGGING flayling wolfer test..
I bet 400wpc will do it. I will put on goggles and ITS ON!
I will call it my own form of THX certification.

Ill will post results...
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