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... |
Spluta: As i mentioned above, feeding a high level signal that is below the point of resonance to a vented speaker system will cause the woofer to throw wildly i.e. make excursions that can be dangerous to the woofer itself. I doubt that this is the situation with this specific case though as there really isn't a great amount of deep bass in the THX intro to that movie. Sean
> |
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. |
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
> |
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 |
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. |
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. |
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 . . . . |
I have no reason to doubt the above posts about speaker damage resulting from the Star Wars DVD, but since 100,000s of copies of this disc have been sold/rented, then why aren't we hearing reports in the media of tens of thousands of damaged HT setups? If this disc is causing damage to high end speakers with hefty power handling capacities, then I can only imagine what its doing to a typical sub $1,000 real world system. |
Bishopwill: You mentioned something that i thought of also, but doubted ( or at least hoped ) that Avimar's amp ( Halcro ) wasn't failing in the manner that it would take to pop the woofer. I also "assumed" that the woofer of a "good" speaker would be strong enough to take "abuse", yet they did pop.
During severe clipping, some amps will pass sizable amounts of DC voltage. Putting DC voltage into a speaker is akin to instant "thermo-nuclear" heat build-up in the voice call. Adding sizable amounts of music ( AC ) on top of the DC heat being developed during sustained clipping and you can literally "melt" the windings of the voice coil of a driver. In severe situations, one can literally "flame out" a driver i.e. you see flames coming out of the speaker cone near the dust cap ( circle covering the voice coil ). If you ever see this happen jsut once, you'll never forget it. It will initially scare the hell out of you. GUARANTEED !!! Once you've dealt with the situation and the shock has worn off, your memory will be of an "awesome" event i.e. the stuff that "audiophile tall-tales" are made of.
As it turns out, my girlfriend borrowed the "Attack of the Clones" disc from her mother this last weekend. I'm going to fire it up later this week and see what happens. My guess is that i'll be fine due to the fact that i'm running sealed speakers. I'm thinking that the center frequency of the "blast" is tuned below the resonance of the port on most speakers, which causes the driver to become "unloaded" at very high volume. This results in the woofer flailing about wildly with the amplifier offering little to no control. Obviously, this is VERY tough on the driver and sometimes results in complete and total devastation of the driver(s).
If you think of a badly warped record being played on vented speakers, you might be able to picture a SMALL part of what is taking place. The same thing is taking place, but on a much more intense and consistent level. This can take place in a subwoofer just as it can in a "standard" speaker. That is, if the subwoofer is vented ( port, passive radiator, slot loading, etc... ). In a sealed and stuffed speaker system, the natural "air spring" within the box helps to minimize "bass slop" / excess excursion and keep the driver under control. Sean
> |
Sean, you said it perfectly. What the hell has become of High End? Smoke and mirrors man, Smoke and mirrors!! |
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,
You said 75db do you mean the display on your preamp shows 75db? If so, that is not how the setup works. You can not go by the number on the display because different power amps and speakers have different sensivitives. You need to run a test signal and measure with a SPL meter at the listening position. Someone said it should be 85db, some said 75. I don't know what is right but I will go by the lower number just to be safe.
On the other hand, if you did measure with a SPL and your speaker begain being stressed than I think your room maybe too large for your speakers. A speaker should not show stress at 75db at the listening position.
My comments were based on what I understand from your message. I could be totally wrong here because I don't quite understand what you meant by 100db for busy redbook and 105db for DVD-A. |
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? |
I don't watch too much movies so I don't really know what reference level is correct but I think if you listen at over 100db level, you might be risking yourself to permanent hearing damages. |
Spluta- You probably don't have your system set to video reference levels. When properly calibrated, you will see transients (as per the spec of dolby digital ex) well above 100 db. I believe 115 db is the transient max for Dolby Digital EX but I have measured some movies in excess of 120 db. With the Star Wars Attack of the Clones turned down a good 10 dB from reference, I am really taxing my MBL subwoofers. At reference level in a decent sized room, I can see how someone could blow a driver out on some of the explosions in the movie.
To properly set the reference level of your HT to movie theater standard, you need to calibrate each of your speakers to 85 dB with Avia when your processor is set to reference volume. Most processors set reference to 75 dB but this is innacurate. |
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! |
$1200 for one woofer? Glad I cant afford those speakers (big lie). I once blew both tweeters on some Mission speakers with a clipping 300wpc amp. They were almost new and the local super-store exchanged them on the spot. This was 15 years ago, a friend still uses them. Cheap speakers, great service!
I like to run (stereo) 2-way speakers full range with 2 subs and find that occasional dynamic peaks in the lows can over tax the woofers in my monitors. DVD engineers need to get a grip, how loud does a bang need to be? |
I have played this DVD on both my HT system (Paradigm 100 V2 and VMPS Larger Subwoofer) and on my music system (Mezzo Utopias), both at higher levels than I would ever do normally. The Utopia woofers suffered no damage whatsoever and did not bottom out, though their output was obviously less than the VMPS sub. I can't help but believe that you experienced an amp problem. We tend to think of only tweeters being damaged by clipping but I suppose it could happen to woofers, as well. Sean, does this sound plausible?
I agree that you should raise holy hell with your dealer and with the mfgr about warranty coverage of only one woofer. Absurd!
will |
I agree with foreverhifi. On video apps I have my subs pick up everything below 80hz. I don't want to overload my mains even though they are quit capable. On two channel or other audio I have the subs pick up below 50hz. This way I don't overload bass on my music and get the complimentary effect with my mains. I am however intrigued by the new stars wars dvd. The helicopter scene in Matrix makes my bones rattle. Can't wait to hear this. |
sounds like you have a similar setup as me.. apart that I have Wilsons. What I did was buy two subs (left and Right) and put the main on a cross-over at 40hz.
I rather blow my subs then main speakers... BTW.. my Subs bottomed out at one point in the movie.. I think it was at that point
Matt
http://members.rogers.com/mzn50/ |
Ooops!..I meant Dunlavy SCV's, not SCIV's!(when refering to the Dun's being overdriven...sorry. |
YOW !!!! This makes me want to run out and buy this DVD just to see how much "devastation" i can accomplish. Thanks for the warning : )
As to the damage done to the JM Lab's, i would raise hell with your dealer and the importer. Ask them how some little "weenie" speakers can achieve THX certification and take the beating while these supposed mega-dollar speakers explode when pushed hard ? Covering only ONE driver ??? Talk about a "K-Mart" warranty.
Personally, i would do whatever it would take to get them to cover the damage under warranty and then sell them. Who wants a speaker that you can't watch movies with ( regardless of the type of soundtrack ) and / or get a hassle from the manufacturer / dealer when it comes time for them to stand behind a multiple thousand dollar product ?!?!?!? As to ONE of the woofers costing $1200, that is utterly and completely ridiculous. I hate to add insult to injury, but it is this kind of stuff that absolutely makes me abhor much of what "hi-end" has become. Sean
> |
I'm currious to know what amp you are driving your Utopias with ?
It appears to me that this is another case, in my experience with HT systems, where THE POWERED SUB SHOULD BE HANDLING THE BASS!
PASSIVE speaker systems, LARGELY should not be handling demanding bass from dd/dts soundtracks! I know far too many people play there "full range" speakers as "large" for movies in a "passive speaker system". And it's never going to have enough control over the bass drivers in a PASSIVE speaker to handle bass properly! I can CLEARLY overdrive the bass woofers on a pair of large Dunlavy SCIV's (4 X 12" woofers)when playing full range on some of the movie mixes out there. And I can do the same on other large speakers. I don't seem to have this kind of challenge driving active woofer designs, like Def Tech BP2000's or Infinity Prelude MTS's!!!
I've said it time and time again...."Unless you're using full range speakers WITH ACTIVE POWERED WOOFERS, you should be configuring your speakers as "small" on your pre/pro, and letting the ACTIVE POWERED sub handle the bass!!
The damping factor and control that's possible through PASSIVE CROSSOVER NETWORKS, isn't sufficient for dynamic transparancy in the bass reigion at the very least. In a powered subwoofer, the AMPLIFIER is RIGHT ON TOP of the bass driver, utilizing "TIGHTFISTED" control over the driver.
There's a reason THX has specified a 80hz setting for it's processing between bass woofer and main speakers...because it works!!!!
I bet what happened here was a case of Amplifier clipping, which cause the woofers to overheat and melt the voice coils! What Did JM Labs Say?
Anyway, my theory... |
Phew!!! I would seriously look at www.zalytron.com to see if you can purchase the replacement speakers from them. I think they would be much less.
I agree the intro with the exploding sphere is out there. I have a good sub and it literally rattled my house the first time we played it. My 3 year old came running from down the hall all upset!
Good luck, I hope zalytron can help you. |
Didn't blow any woofers, but when the seismic charge went off later in the movie, all the power in my house went out for about 10 seconds. (Of course, that may have been a coincidence -- but I doubt it.) I was listening at the same levels I listen to any other action-oriented movie at, too. |
