Blown subs - Curious as to why....

[wsu99999 10+ year member]

Hey Guys -

This is my 1st post, I've been reading these forums for years, but didn't even become a member until yesterday...

Here's my problem. I took some old equipment to a local car audio shop to have it all installed. The equipment is as follows... 2x Kicker L5 12's, and 2x JBL BP600.1's.

It got installed (into my 98 Cadillac Deville), and everything bumped great, but I was having huge power drains when large bass notes hit. I took it to the shop and they installed a 100 Farad battery in the trunk. 10 min out of the shop, Speaker # 1 goes up in smoke...

The next day I have them give me a new single box for the remaining Kicker, take out the battery (cause I clearly don't need it w/ one woofer), and hook the remaining Kicker up to one amp.... 10 min out of the shop, the other woofer blows.

I'm curious as to why. These bumped in my car for a good month prior to the battery install. Is it a coincidence that they both blew after the changes to the wiring, or did the shop do something wrong? I know it's tough to tell w/o looking at it, but what are your thoughts.

I doubt there is much I can do, except not use that shop anymore, but I want to know if it was there fault, or if it was just time for the woofers to go.

Thanks for your help.

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[Bumpin' Goalie 10+ year member]

My first thing would be to check how the amp was set.

Second, would be check wiring.

Most blown woofers that I see like this are usually user error. Not blaming you, just saying usually they get clipped without the user knowing it.

It happens a lot when people push their equipment past safe limits to get it louder.

 

[wsu99999 10+ year member]

The amp had a gain set up about 2/3rds of the way full. It's hard to tell exactly, these amps don't have clear indicators of where they are set, it's really a guessing game as only the max and minimum are labeled (honestly, I"m not even sure if they are labeled). No bass boost, lpf set around 60hz or so, it's really hard to tell as there isn't clear marking.

The bottom line is I wasn't listening to them THAT excessive, sure I was bumping, but like I said before, I bumped these for about a month prior to the battery install and no issues.

The ONLY theory I can come up with is as follows....

When they installed the battery, it increased the voltage and wattage on long bass notes. This added more power to the subs, which they couldn't handle, and one blew.

When the 2nd sub was in there alone w/ only one amp, the same thing applied - since the voltage increased, the amp was performing better, thus, blown speaker.

I just wouldn't think a speaker rated at 600w RMS would be blown by a 600W rms amp. I guess it happens, but I have a good friend that has 2 1250W Kicker Amps going to his L7's, and he has only blown one in 5 years. I just found it odd that both went in a period of 24 hours after a major change to the system.

If there were an issue with wiring, what would the most common culprit be?

 

[wsu99999 10+ year member]

And the reason I want to find out if it's the shop's fault isn't to go stick it to them. I actually really liked the guys and they hooked me up w/ a free box for the single solobaric, and also took my power cap and deducted it from the price of the battery (which they charged 150 for a 100 farad battery, and gave me 100 bucks for my 1.5 farad cap - so the total price for the battery for me was 100 bucks (50 price difference, 50 labor).

They seem like cool guys, but I wasn't very impressed with the actual install. It didn't look very professional. They didn't clean up well afterward, didn't reattach my trunk lining properly. Just little things. I was just afraid that if the clean up wasn't professional, the install may not have been either. And if it is an install issue, I don't want them hooking up my next system (as I plan on investing much more money)

 

[Bumpin' Goalie 10+ year member]

Amp could have sent clipped signal from being pushed too hard, clipped signal can create VC's to heat up extremely fast, blown.

Not saying this is the answer, but it is a possibility.

Maybe google amp clipping, clipped signal, etc to grasp what I mean.

I am sorry for your loss regardless of cause.

 

[MONSONwarrior Premium Member]

Use a DMM to check the voltage they had your amp set at and see if it's near where it should be. The equations is sqrt(volts*impedence)