Experts: need your help

emagdnim8 · Sep 25, 2008, 09:30 PM

My subwoofer stopped bumpin today. All connections and fuses are fine. However, when I push the cone in a little bit, it makes sound.
Is this a symptom of a blown sub?

Red_Evolution · Sep 26, 2008, 12:28 AM

did you check the fuse at ur battery??? and ur fuse on your amp?? what kind of a sound is it making?

emagdnim8 · Sep 26, 2008, 12:57 AM

All of the fuses are fine and the amp has power. The sub plays normal sound only when I push down on the cone. Any ideas why?

magyar86 · Sep 26, 2008, 01:03 AM

its been a while since ive been in the audio biz but the reason you hear sound when you push the cone in is because the voice coil is out of alignment, probably due to spider failure. the voice coil is jut a bunch of wound copper wire wit a neg. charge that sits inside the magnet witch is positively charged or vice versa cant remember. and that polarity diff is what makes the speaker move thus creating sound waves. so the voice coil is too far out so when you push it down i get back where it needs to be and starts creating sound again. so long story short you need a new sub...

emagdnim8 · Sep 26, 2008, 01:10 AM

Thank you.

Is this something that could possibly be caused by the sub being in a car that's on coilovers? Or too much power going to the sub?

magyar86 · Sep 26, 2008, 01:58 AM

i dont think that c/o's would cause this problem. the vibrations from the sub itself is far more than your car could ever produce. and i dont think its from overpowering. i would say that it was due to a defect or the main thing that happens is the voice coil was not properly broke in. think of it like a piece of hard plastic..if you bend that plastic very fast it will likely snap or at least become weaked. but if you slow work that plastic a little at a time the plastic will become flexable and not break/snap. so if your sub wasnt broke in the glue, voice coil, spider, etc could have failed due to that. subs need to be broke in like a clutch/motor. there are things you can buy that plug into a wall outlet and give it low watts for a 24 hour period to break it in....or you just have to be gentle with it for a week or so. so IMO it was caused for either not being broke in correctly or just a mfg defect.

biggie5252 · Sep 26, 2008, 11:03 AM

Not breaking in a sub shouldn't cause any damage. It might not last as long, but it shouldn't actually break it.

Underpowering a sub, causing the amp to clip, will do more damage than overpowering, unless it's grossly overpowered.

Do you have an ohmmeter? If so what does the sub read?

emagdnim8 · Sep 26, 2008, 12:16 PM

I don't have an ohmmeter.

The sub was a Boston G210. The amp is a Boston GT22.

magyar86 · Sep 26, 2008, 12:27 PM

Quote:

Originally Posted by biggie5252

Not breaking in a sub shouldn't cause any damage. It might not last as long, but it shouldn't actually break it.

Underpowering a sub, causing the amp to clip, will do more damage than overpowering, unless it's grossly overpowered.

Do you have an ohmmeter? If so what does the sub read?

i agree, it wont cause and immediate damage but it will weakin the glue/v.c's etc, so in the long run it will cause the a failure, not always but sometimes. to only reason i say this is because of the symptoms he says the sub has, (wont play unless he pushes down on the cone) witch leads me to believe that there was a spider failure, the spider is what keeps the voice coil(s) in the persice location while still allowing it to move in and out. so when the spider fails the voice coil will not be in the correct place and there will be no magnetic push/pull and thus producing no sound, and when he pushes down on it the voice coil it gets back where it needs to be a you get sound.

and yes pushing a amp too far and causing clipped sound waves will damage a sub but that would cause a voice coil failure not spider. the voice could is fine (just out of allingment) since it makes sound when the cone is pushed in.

i have seen subs do this many times before, sometimes they can be fixxed with a new spider/re glue. but unless its a expensive sub i would just get a new one unless its like a solo x or something that you can simply swap out everything.

but again this is just my opinion and i could be dead wrong!

magyar86 · Sep 26, 2008, 12:36 PM

here is a diagram of basically how a speaker works. you can see that the spider is what keeps the voice coil centered inside the magnet, so if it fails then the voice coil cant do its thing...

http://static.howstuffworks.com/flas...er-working.swf

biggie5252 · Sep 26, 2008, 01:09 PM

I didn't realize it actually played music when he pushed it in. I thought it was making A sound, like the scratching of a toasted coil.

An enclosure that's too big can cause woofer suspension failure also although over time and not sudden like the OP is describing.

So you've actually seen woofer failure where the coil actually falls out of the gap so far to where it won't play? What did the surround look like on these woofers? The surround alone should pull/push it back into the gap. What kinda woofers were they? I'm not trying to start an argument, it just doesn't seem very likely.

OP, what kinda enclosure do you have? Can you easily push the woofer in till it bottoms out? Is you woofer facing up or to the rear/front of the car?

matt55 · Sep 26, 2008, 02:27 PM

Sounds to me the VC windings became unraveled (melted the epoxy that holds the windings to the former) and now looks something like a ''Slinky" .
I dont think the VC jumped out of the gap .
But either way I see a new Sub in your future .

emagdnim8 · Sep 26, 2008, 02:37 PM

Quote:

Originally Posted by biggie5252

OP, what kinda enclosure do you have? Can you easily push the woofer in till it bottoms out? Is you woofer facing up or to the rear/front of the car?

This is the enclosure.
There isn't more or less resistance when pushing on the cone. The woofer pushes in the same as it always did. It is sitting in the back of the trunk facing the rear of the car.

biggie5252 · Sep 26, 2008, 03:10 PM

It's more than likely not a suspension issue. It's really sounds like an electrical issue. I don't think the VC unraveled either or you'd hear it scratching as you pushed it in. There's very little clearance between it and the motor structure. You really should go get an ohmmeter and read the coils. You should be able to get one for less than 20 bucks and they come in pretty handy. Do you have another speaker/woofer you can swap out?

Is the woofer still under warranty? If it is, just take it back.

magyar86 · Sep 26, 2008, 03:20 PM

i guess i didnt type it how i ment it to sound lol. i didnt mean that the voice coil comes out of the motor structure, i just ment that its not in the correct allignment. bad choice of words on my part when i said it was too far out.

yes the surround will keep it somewhat in the correct allignment but the spider takes the brunt force of that.

op how are you seein the VC? is the spider still intact? usually you cant see a VC...unless maybe somehow you are seeing it through the air hole in the back??

but if infact the vc is unraveling then that is probably a mfg defect and you should be able to get it fixed through boston.