Subwoofer keeps blowing for unknown reason...

[USNSCPO]

Just some food for thought.....

(1) try setting your crossover to 80-90hz; (2) keep the bass boost dial turned down and only adjust your gain... In my opinion, our cars already have enough cabin gain. Using bass boost turns everything boomy and muddy. I highly recommend about 1/2 on the gain if you're driving the amp straight off the headunit output. Do this and your amp will: (1) clip much less and (2) clipping, if it happens, should not rise high enough to permanently damage your drivers. Oh, and a subsonic filter (basically a high pass filter of 15-20hz) would be a good thing for any sub install.

The premium system headunit puts out something like 5volts AC for the music signal-- it also has a 6volt DC ground loop signal present that "should" be killed with a ground loop isolator. If the amp hasn't died yet, then apparently its ok with the 6vdc?

Also, C5 user TeamTCA (a past World Champion in SQL) has discovered that the headunit's built-in equalization (even if adjusted flat) is no where near flat, and is tuned to the factory speakers. Not necessary a good thing for aftermarket amps and drivers. The worst part of the factory EQ is a significant mid-bass peak of 200-300hz and is high enough that no one (who's tried) has been able to completely eliminate it. I mention the mid-bass peak because if you're crossed over too high, this could be one of the causes. 200-300hz is within vocal range of some men, non-digital drums, and horns. If you hear any vocals in your subs at all, you're crossed way too high.
Good luck!

[Topdown]

There are details to this that we are all missing... we need more information to be able to help diagnose the problem.

Details on how/what is "blown"
Details on environment - is it wet? dry? hot? cold?
if possible, snap some pics and post them up...

I am beginning to lean toward the enclosure as the culprit - enclosure problems are the only things I have seen tear a good woofer apart, though I have seen lots of environments (wet for example) damage them.

[jslim]

A few years ago I remember alpine having an issue with a batch of type r's that had gotten a bad batch of glue and were coming apart. If you have a old type r (before the ridged rubber surround) that could be the issue. What is the source unit. Dirty signal in makes horrible signal out of the amp. Subs dont blow because they are "overpowerd". Remeber you are dealing with signal and if the signal is not clean than you get distortion and then a blown coil. If your running a 12" sub set your crossover at 60 hz and see if that helps. Like others have said we need more info and pictures would really help.

[mrray13]

Cone coming undone could be bad glue as previously mentioned, but it can also be caused by beating the sub to death. That can be done several ways...

Enclosure too big for sub, power applied. It's going beyond it's mechanical limits.

If it's porter, and you aren't running a subsonic filter, you are dropping below tuning frequency, unloading the sub, driving it beyond it's mechanical limits.

You are just flat over driving the sub. Too much power plus constant cranking on the volume knob, driving the sub beyond mechanical limits.

And combo above, and faulty glue. Although two different brand subs doing the same thing? Leads me to believe it's in the system/user, not product, although that's not impossible. Needs complete details of system, with pics of subs, amp settings, to be sure.


Jslim....you can't blow a sub by overpowering it? Really? Just what do you think clipping an amp is? That square wave is twice the power of a sine, and if that power is within the rme power handling of the sub, it'll eat it all day long. Distortion, square waves, only kill if it goes above what a sub is rated for, and then it has to be maintained for awhile. Almost all subs can handle twice, maybe three times their rms,hence peak ratings, ratings for brief moments. That's the beauty of music, it's dynamic.

In any case, if you don't think you can't blow a sub by overpowering it, you haven't played with enough power. Try this, plug your sub, free air, into a 110 outlet. That's a 3600wrms sine wave, roughly, at 60hz. Very few subs can handle that. Some even get on fire, so do it outside, lol!

[Topdown]

Originally Posted by mrray13

Some even get on fire, so do it outside, lol!

heheh used to do that to swap meet tweeters in high-school... the smell is HORRIBLE

The first time you light a sub on fire in your car is similar to the first time you kiss a girl... slightly terrifying, something you'll never forget... and it rarely goes well

*sniff* makes me miss my old Orion HCCA amps and that fateful day that I lost a very close friend... an M&M Godfather 15... *sniff* :(

[Epitaph]

You need a new "audio guy". That's all there is to it.

[mrray13]

Originally Posted by Topdown

heheh used to do that to swap meet tweeters in high-school... the smell is HORRIBLE

The first time you light a sub on fire in your car is similar to the first time you kiss a girl... slightly terrifying, something you'll never forget... and it rarely goes well

*sniff* makes me miss my old Orion HCCA amps and that fateful day that I lost a very close friend... an M&M Godfather 15... *sniff* :(

My favorite was one of three ID SPLs that were handbuilt for a friend in DB Drag. I got a hold of the subs when Shane was through with them and plugged one into the wall. We got a full 30 seconds of watching that monster dance across my garage floor before it locked up! It was freaking awesome and loud!