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Here is my report on this, Last night i took the EQ off of the sub like suggested and put the amp on half way and watched the passage. ---No pop noise occured.

I then went a notch higher, again, Nothing

I went a notch higher, again, nothing (should have popped by now)

I got a little gutsy and went 3/4.. cone completely dented.... Just kidding. Nothing happened. The cone flexed really hard but no pop

So i wrote on here that it was the EQ doing it. However, i thought about it and realized that i hadn't played with the TRON passage since i messed with Calibrating the Subwoofer to the receiver. At least i couldn't remember if i had. So it seemed unfair to blame the EQ.

So just now i played the passage again without the EQ, Played perfectly fine.

I put the EQ on and played (still at 3/4) but at a lower volume on receiver. POP!!!! so turned it down a couple notches Again POP!!! (only softer) Turned it down some more. NOTHING
Thoughts on this?
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OK analyzing the results of your experiment above:
first, there is nothing wrong with the EQ, nothing wrong with the amp, nothing wrong with the Ultra.
There IS a voltage and power issue between the EQ and the amp. With the EQ boosting the infrasonics going to the front end (input) of the amp, the low .775 volt setting is being overloaded while playing the passage of TRON and any other sound source with that particular set of SPL variables. I believe THAT"S where the "POP" sounds is originating NOT the Ultra.
The cure? Turn down the receiver volume, you're at the limit of the EQ and amp combination . . . . for the time being. Since the EQ doesn't give you a way to "fine tune" the response curve going to the amp, you might consider different EQ equipment like a Behringer DSP1124, or equivalent. There is more versatility in a unit like that PLUS you'll be able to use the higher voltage (1.4 volts) setting on the Crown amp. The Behringer has a volume control of it's own and you could perfectly match the voltage going into the amp to best fit the TRON playback track.
You DO need to EQ the Ultra to make best use of it's potential in the infrasonic region ie: 5Hz to 25Hz. Without EQ the Ultra is just another sub.
I'm curious though, when you hit the high SPL in TRON with the EQ/amp combo in place, what is the Ultra cone doing? Is the cone reaching full travel? When you bottom an Ultra, that cone is REALLY jumping! I've bridged my Crown XTi 4000 and had the cooling fan activated and running and the output hot to the touch playing 10HZ test tones without bottoming. The amp failed before the LMS bottomed. Scared the stuff outta me when the amp protection made a "BRAP" sound through the driver and I shut it down. The protection circuit oscillated while it attempted to shut down the power supply.
In your case I think the input circuit oscillates (pops) as the incoming signal exceeds the .775 circuit limitation.
I don't remember if you described how you wired the voice coils on the Ultra. Are they in series or parallel?
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Robert, have you bottomed any of your LMSs? If anybody has the amplifier power to bottom an LMS, YOU do!
 

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This LMS Ultra isn't mine but I still have nightmares to this day:scared:

! WOW! First time I've seen THAT. I'll bet the owner plugged the driver directly into a 220 dryer outlet!
Wait a minute wait a minute! That's not a full LMS driver, that's a passive radiator that someone stepped on.
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Right Robert???
 

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The Data- bass site will answer all your questions as to the performance of the LMS- both 5400 and Ultra.

Josh said the Crest amp ran out of steam before the sub bottomed and that was the exact same amp I saw pushing the driver when it was dimpling the surround.
 

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The QSC PL 9 was plugged into a normal 20amp 110v outlet. That is why it's important to check how hot you are running your LMS Ultra compared to your mains with a big amp. The LMS Ultra likes a lot of power but it has it's limits and when you reach them you pay big time.
 

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For full disclosure I believe the sealed enclosures were too big in the first place. 6cuft is a size I would use for dual LMS Ultra's not a single.
 

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Anyway, I remember a little tidbit about the LMS that few might not remember. The cones were originally in titanium, with no color, but the polish was hard to achieve and the cost was astounding to mill and form it in relation to the aluminum. Therefore, against better judgement, the driver was aluminum and there you have it.
 

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remember, tc sounds drivers were mostly polished aluminum cones, but the LMS was a different beast. I remember the day it popped up on the web. I wanted it from the moment I saw it. But, manufacturing problems and vendor problems crept up and things turned bad. If Kyle Lee is trolling around, he could answer this better, but I can say that if the driver you have i n that picture is titanium, it was subjected to some serious force. The titanium cones were subjected to a man standing on them with no deformation, I know the aluminum one would crinkle like a beer can from that
 

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Your still at the height of subwoofer tech Robert. I sold my LMS Ultra pair only because I enjoying building but the Sound Quality of my LMS beat every other high dollar commercial subs I have ever owned. The most musical sub was the JL Audio F113 but I needed more SPL for movies. The LMS not only matched the $3,500 single F113 for music but surpassed it by leaps and bounds for movies and that is when I got hooked on DIY.
 
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