ooohh nooooooo!

[Beatin' 10+ year member]

nooooooo!!

I was ballin' down the street full tilt. Then, gradually, I started to hear this loud distortion. It was a "mechanical" sound, like it was clipping, but it wasn't. I came home and checked everything, amp is fine, box had loose screws and brackets. I tightened everything up and tested it. Still making noise! WTF! It happens at near full volume and at certain frequencies.

I took the bandpass box cover to check the woofers. No loose dust caps, sealed section is sealed well when pushing the cone in by hand. No scratching when pushing the cones. Sub screws are tight, coils read 1 ohm each (dual 2ohms paralled), everything box related seems fine, no air leaks, no loose port, etc. WTF is going on?

The sound is very loud from inside the cabin. It's not the license plate or anything like that. It sounds like it's coming from the box. I'm guessing one of the coils ripped a glue joint, because the surrounds are fine.

wtf man.....

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[Bobbytwonames 5,000+ posts]

Did you smell the coil(s) burning at all? It sounds like you lost a coil to me.

 

[just call me KeV 10+ year member]

Could it be the triple joint or torn at the spider landing? Maybe it would allow you to push in and not feel inteference or improper alignment.
Change in having your windows down on certain tracks causing the subs to unload?
I would be interested to know as well. Here to learn and all.

 

[mat3833 10+ year member]

One of the downsides of bandpass... You possibly tore a spider or potentially a failed spider-to-coil connection.

Before you do anything pull the woofers out. They might be eaisely repaired.

 

[Beatin' 10+ year member]

Did you smell the coil(s) burning at all? It sounds like you lost a coil to me.

No they both read 1 ohm correctly. At full tilt there's some loss of output but the noise is overwhelming. Also no smell at all. I know for sure I was never overpowering the subs. 2.5in coils rated 500wrms each. They never saw more than 1000wrms together.

Could it be the triple joint or torn at the spider landing? Maybe it would allow you to push in and not feel inteference or improper alignment.
Change in having your windows down on certain tracks causing the subs to unload?
I would be interested to know as well. Here to learn and all.

They're in a 4th order bandpass box so unloading is not the problem. But I'm thinking the full tilt 2,200watt kick drums on some of my music may have ripped the former/coil from the spider or cone. I would have to take them out to see which one is damaged. They say 4th order bandpass boxes severely damp subs cone movement so it makes sense that former/coil could've ripped away.

Tomorrow I'll have to take them out and see what happened. I'm not 100% that may even be the problem.

One of the downsides of bandpass... You possibly tore a spider or potentially a failed spider-to-coil connection.

Before you do anything pull the woofers out. They might be eaisely repaired.

That's the plan. Gotta see if they're repairable. If not, then I will have to cry.

Then I will get 4 18's.

 

[1aespinoza 10+ year member]

The sound is very loud from inside the cabin. It's not the license plate or anything like that. It sounds like it's coming from the box. I'm guessing one of the coils ripped a glue joint, because the surrounds are fine.

Sealed boxes put pressure on the dustcap. Run a fingernail on the circumfrence to see if that is the issue. I have some 8" Skars that tore the lead's thread making distortionlike noise, but it was at all volumes.

 

[Beatin' 10+ year member]

Sealed boxes put pressure on the dustcap. Run a fingernail on the circumfrence to see if that is the issue. I have some 8" Skars that tore the lead's thread making distortionlike noise, but it was at all volumes.

I did check the dust caps and they're glued on nicely. The more I think about it, the more I think it is a loose former/coil that ripped off the glue joint either on the spider or cone, because the sound gets REAL BAD at high volume, like the coil is slapping the bottom of the motor and the cone at it cycles and reaches higher excursion.

man I can't believe this happened. I'm out here running half ohm, thinking the amp might go out, end up tearing apart the woofer.

 

[Bobbytwonames 5,000+ posts]

I did check the dust caps and they're glued on nicely. The more I think about it, the more I think it is a loose former/coil that ripped off the glue joint either on the spider or cone, because the sound gets REAL BAD at high volume, like the coil is slapping the bottom of the motor and the cone at it cycles and reaches higher excursion.

man I can't believe this happened. I'm out here running half ohm, thinking the amp might go out, end up tearing apart the woofer.

Which amp? Why are you running .5 ohm?

 

[Beatin' 10+ year member]

Which amp? Why are you running .5 ohm?

Precision Power BK1800.1D

Subs are dual 2 ohm, all paralleled to half ohm.

 

[Bobbytwonames 5,000+ posts]

Precision Power BK1800.1D

Subs are dual 2 ohm, all paralleled to half ohm.

You probably should've just wired to two ohms. It's hard to say if you wiring to .5 ohm caused your problem.

 

[audiobaun 5,000+ posts]

Sounds like those subs bottomed out for too long. Ill bet the spiders are torn .

 

[1aespinoza 10+ year member]

The more I think about it, the more I think it is a loose former/coil that ripped off the glue joint either on the spider or cone, because the sound gets REAL BAD at high volume, like the coil is slapping the bottom of the motor and the cone at it cycles and reaches higher excursion.

I have no experience on loose coils but I doubt an unglued coil would stay centered without lodging in the v.c. gap. I did however have a pair of 12" Fosgates that acted just like you described. I ended up wrapping shoe laces at the cone/spider junction to solve the issue. Yup, I pulled a McGuyver.

 

[mat3833 10+ year member]

I did check the dust caps and they're glued on nicely. The more I think about it, the more I think it is a loose former/coil that ripped off the glue joint either on the spider or cone, because the sound gets REAL BAD at high volume, like the coil is slapping the bottom of the motor and the cone at it cycles and reaches higher excursion.

man I can't believe this happened. I'm out here running half ohm, thinking the amp might go out, end up tearing apart the woofer.

Bandpass boxes are incredibly hard on cones/spiders. Sure, you can quickly cook a coil in one too, but you are putting a ton of pressure on the mechanical bits of a sub running bandpass.

 

[Buck 5,000+ posts]

Yeah, 4th orders can put a ton of stresses on a woofer. I specifically avoid 4th order BP’s above a certain power level, unless your subs are designed to work sealed. Series 6th’s are where it’s at.

Can you state the specs of your sealed section and exactly what subs and power you have?

 

[Beatin' 10+ year member]

Yeah, 4th orders can put a ton of stresses on a woofer. I specifically avoid 4th order BP’s above a certain power level, unless your subs are designed to work sealed. Series 6th’s are where it’s at.

Can you state the specs of your sealed section and exactly what subs and power you have?

Audiotechnix strato D2 1.85cu/ft net sealed per sub, 1.7cu/ft ported chamber. Each sub has it's own box. 1800wrms but pushin to about 2200-2300watts musically.

I isolated which sub was making the noise and took out the sub in question.................there's NOTHING WRONG with it.☠☠

Coils look nice, no scratching, no ripped spider or glue joints, cone, dust cap, etc ,etc, etc.

What.....the.....fukk. I'm at a loss. I don't know any more.

I noticed that box has some leakage when pushing the cone in. It's not bad, but could that contribute to the issue? I mean it still takes time for the cone to get up after pushing it in, but you can hear a whistle when pushed in.