coil failure after 4 mins in kicker L7
 

i am having a difficult time getting any answers to my questions so i thought i might try here at CCA.

i replaced the coils in my 12 inch kicker L7 i went out today to give them a try and at 40 hertz it took about 4 mins till i had smoke coming out the port in the box.

what looks like has happened is the coil former is made out of paper and the coil actually came off of the former and got all squashed down inside the magnet. i bought these speakers blown up and the stock kicker coil seems to have a coil former made of resin. and the burnt coil i pulled from it was just burnt in 1 spot but still intact. this replacement coil seems to be burnt a little but is like 50 feet long and all unwound.

i saw that kicker (and im asumming others) have speakers that have replaceable motors, and i thought i could do something like this with a set of
L7s. i machined a outer ring for the surround and one for the spider. the only thing is i still need to glue the coil in place. im new to this but im thinking 4 mins is a unusually short lifespan for a speaker. i dont mind replacing these coils i kind of expect to.

for the initial test i ran the speaker with a 40hz tone for 4 mins with a jbl bp1200.1. i realize this amp is over kill but the sub didnt distort or bottom out or complain at all. (till all the smoke, then it just died).

so my questions to anyone in "the know" are.....

1. is it normal to have formers made of this plasticky/paper stuff? or resin a prefered medium, or is there even any difference
2. should i go punch this guy in the stomach for selling me an inferior coil or should i buy another one from him? and this time just relax with the 40 hz / 1500 watt test
3 does anyone know where to buy reputable coils from?
4 can anyone link me to a site to ask the rebuild questions

you sent 1200rms into a woofer that is rated for 750rms...

you sent the thing into thermal failure. thats nobodys falt but yours.

LoLz high five for pushing l7's

hahahahaha thanks man i seem to be getting a lot "your an idiot" all over the internet. i managed to heat the entire magnet so hot that i deformed the rubber ring around the magnet

does anyone know where to buy new coils from?

how do i prevent this from happening again? aisde from using my tone generator anymore? i want these speakers to be pushed right to their limits. and now i am certain i can do it with these amps. but i would think that the speaker should start to bottom out or distort if i put too much power to it?

Hey don't worry man, you're not the only one do to things like this. I learned my lesson after blowing a pair of home speakers years ago.

Try to match the RMS to the speaker and try not to distort :D.

1500 watts... hehehehe 40Hz for 4 minutes... hehehehehe what frequency is your box tuned to?


heheheheeee

thanks I needed a laugh badly, I had a horrible Christmas with 6 adults and 4 grandchildren at my house for 2 weeks... went off the wagon (I was on it for 5 years) last night and drank myself to sleep... thanks again

as john above is laughing i'll see if i can explain the issue
The tones is a 40hz sine wave, meaning constant power and no breaks?
If that is right then as jalat said earlier you a smoking the coils with too much heat.
If you were playing for shorter periods I am sure it would take it fine, the way to look at it is music has breaks and variation which gives the woofer time to cool, tones don't. Imaging your revving and engine, you eventually need to let off of your going to overheat it. So it seems your not at the limit of power more the thermal handling over time, if you were to do burps like the spl guys do you could probably throw more at it.

Yeah, but we all know in every other thread, everyone is telling each other to overpower the hell out of everything.
I think it's the fact that he had it on full out (probably) and 40hz for such a long time ... you're almost ASKING for trouble.

I think if he was listening to music daily, this wouldn't have happened. Just don't blast your ish :smilie_da

Not so. Many speakers have suspensions that won't bottom out so you are left with the thermal limits of the driver. If your box is tuned around 40hz, it will minimize the movement of the cone as well, both preventing bottoming and limiting the cooling action of the cone.

yup, that was an entertaining read. Speakers aren't made for sine waves, they're made for music.

But my question goes back to the OP. Why bother with replacing coils when kickers are so cheap to buy new?
And why bother buying blown speakers in the first place?