# Blown L7?



## Zac (Mar 10, 2004)

hello audiophiles;
I have a kicker solo-baric L7 running off a kicker kx1200.1 and it is in a kicker pre fab 3 cubic foot box. today i was driving and listening to at a rather loud volume level for all of 3 minutes and the sub just stopped playing. no blown fuse. amp is still powering up. no loose wires unless internal. the thing i noticed was the sub smells like burning plastic. I dont think this is a blown sub or it would still play and be distorted, right? Anyone have a clue what happened? Did I just kill a really expensive piece of equipment?
BTW: Tweeter did all installs so i'de imagine everything was done properly.


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## sr20dem0n (Mar 19, 2003)

You smelled burned plastic?

Hmm, do you happen to have a multimeter? And definately, whatever you do, do not try to power it on again until you figure it out.


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## droppinbottom (Jun 30, 2003)

man i have seen some subs that would essentially freeze up and would not play once they did. by using a multimeter to check the sub, will not always work the sub can still be blown and test fine


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## sr20dem0n (Mar 19, 2003)

There are a lot of things you can do with a multimeter

1 - set it to measure resistance and hook it to the sub, if it's absurdly low then the sub is blown and trying to power it could fry the amp
2 - set it to measure resistance and hook it to the sub, push on the cone and make sure the resistance changes
3 - set it to measure AC voltage and make sure the amp is actually putting out a signal
etc


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## Zac (Mar 10, 2004)

yea, it's dead . i got it from a show that said they were authorized dealers and the @ssholes just disapeared. they _ _ _ _ ed me over. that smell is the melted internal part of the coil. i also asked them for a dual 2 ohm sub and they gave me dual 4 ohm so i had to run it at 2 ohms. if they gave me the right sub, i could run at 1 ohm and this never would have happened. it is ironic how the only thing i didnt get from an authorized dealer goes bad. the sub was prolly gray market also. i guess this makes me a :dumbass: . now ill either get a dual 2 ohm L7, the brand new JL 13W6--no one has em yet or a 12 inch solo x.


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## sr20dem0n (Mar 19, 2003)

eh, running it at 1ohm vs 2 would give it more power and make it blow faster


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## Zac (Mar 10, 2004)

sr20dem0n said:


> eh, running it at 1ohm vs 2 would give it more power and make it blow faster


But it would have less distortion. All my amp can push is 800-900 rms @ 2 ohms and that is underpowering the sub. It was rated at 1400 @ 1 which hopefully would give it a lil cleaner power and distortion wouldnt kill me sub.


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## sr20dem0n (Mar 19, 2003)

distortion doesn't kill speakers, there are only 2 things that can kill a speaker
1 - too much power - fries the voice coil
2 - too much excursion - rips the spider, cracks the cone, separates the vc former from the cone, etc

If your amp isn't powerful enough for your tastes, and you crank the gain to get the output you want out of it, then you will force it into clipping. When clipping, an amp can put out more power than its rating, and this extra power can fry the sub's voice coil. The same amount of output from an amp that isn't clipping will still blow the speaker though, the only difference is the amp that isn't clipping will sound cleaner as it blows the speaker.


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## Zac (Mar 10, 2004)

Hmm, distortion doesn't kill subs? I always thought and was told that if an amp was pushing at its max load, that when it has 5-15% THD that the distortion can blow, or strongly contribute to blowing, the speaker. Blowing a 100 watt RMS speaker with a 50 watt RMS amp is possible. The Sony X'plode amps don't do a quarter of the power they advertise but I've heard of them totaling speakers.


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## sr20dem0n (Mar 19, 2003)

Right, but it's not the distortion that's killing the speaker, it's the extra power generated by clipping that's killing the speaker. When an amp is clipping it can put out over 2x its rated power, which means that 50rms amp can put out over 100rms when it's fully clipped. This extra power is what fries the speaker, not the fact that this extra power isn't "clean".


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## Zac (Mar 10, 2004)

so in theory wouldnt running @ 1 ohm make it less likely to distort and kill the speaker by clipping if the amp pushes 2x the power in 1 Ohm than it does 2?


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## sr20dem0n (Mar 19, 2003)

The signal would just stay clean all the way up to the speaker's thermal limits, instead of sounding distorted up to the thermal limits. The speaker will be just as loud when it blows as it was before, it'll just sound clean doing it whereas before it most likely sounded distorted because the amp was clipping (atleast I'm assuming it was, those subs can normally handle a little more than their rating, and 900rms is a little below the rating).

If you blew the sub (assuming it wasn't defective) then you pushed it past its thermal limits. Regardless of whether the amp was clipping or not, the amount of power that was being fed to it was too much for it to handle. If you like to listen to the sub at the level it was at when it blew (I can't imagine that, a ported 15L7 on 1000rms is rediculous) then if you do it again, it will simply blow again, even if the power you're feeding it this second time is clean.


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## Chicago Tony (Apr 15, 2003)

The 2003 and 2004 L7's are rated at 750 watts rms. You were feeding it 800 watts running it at 2 oms. Was the box sealed or ported? I don't remember if the Kicker 1200 had a subsonic filter. If it did was it on? Kicker recommends for all vented enclosures. How was the gain set on your amp?

Right now I am running a 12L7 with 1100 watts. L7's are very bulletproof if set up correctly.





NickZac said:


> so in theory wouldnt running @ 1 ohm make it less likely to distort and kill the speaker by clipping if the amp pushes 2x the power in 1 Ohm than it does 2?


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## Zac (Mar 10, 2004)

Tweeter set gain and it was I'de say it was about 3/4 up. It was a vented box, the one kicker sells--bout 3 c/f. It got loud as h#ll. I got plenty of compliments. I may have just overworked the sub a little too much and melted my coil. You prolly have a dual 2 ohm L7 that ur rockin at 1 ohm. I had a dual 4 which I could only run at 2. Im guessing the amp clipped (it was pushing near its max load at 2 ohms) and blew the hell out of it. I may get an 12L72 or just get a Cerwin Vega Stroker <--physically indestructible.


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## sr20dem0n (Mar 19, 2003)

NickZac said:


> Tweeter set gain and it was I'de say it was about 3/4 up.


Damn, that's most likely your problem right there. What preout voltage does your headunit have and what's the range on the amp?



NickZac said:


> a Cerwin Vega Stroker <--physically indestructible.


Hehe, I beg to differ. Mr. Wall Socket has turned many a "indestructible" speaker into a smoldering pile of worthless trash


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## Zac (Mar 10, 2004)

I never looked at gain, I trusted Tweeter. I have a Pioneer Premier HU, one of the 03 models...the DEP something I think? My amp is a Kicker KX1200.1, I dont remember the range off top of my head. Its wattage is 800 RMS @ 2 ohms, 1200 (rated) 1400 (tested) at 1.


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