Why does the surround seperate from the cone on a subwoofer?

[KeithNguyen]

So I've seen this happen twice. This is an Infinity Kappa Perfect 10 DVQ and the rubber surround just separated! Why does this happen? I don't think I was abusing the sub since I actually have the sub turned down to match my system and I do not hear clipping or see the sub bottom out. Right now the sub is sitting in a custom .6x cubic foot fiberglass enclosure with, but with the sub installed it's at .51 cubic feet. I'm using the mid Q magnet insert.

The other time I've seen this happen was with my friend's setup. I made fun of him since I told him it's he has the sub up way to loud, but he wasn't clipping the amp or the sub, so he thought it was fine. He had it replaced under warranty and has since sold his car. His enclosure was about .71 Cubic Feet with the sub installed and he was using the mid q magnet as well.

My question is, why does this happen? Is it the subwoofer? Is it that the enclosure is too small? Is there just too much pressure in the enclosure? Or is it just my luck? Am I pushing it too hard? Good thing it's under warranty, but I don't want to always have to send it out to get fixed. I hear about these things happening, but is it normal?

This is a great sub, it hits nice and hard with tight bass. I was clued off to something wrong when the bass got muddy all of a sudden and I could smell the fiberglass enclosure. HAHA On the drive home, i thought perhaps my enclosure failed, but I was wrong.

Any way, here's a pic to give you a better idea and a bit of entertainment... Note the 10 o'clock area of the sub. The rubber surround is most seperated there.

[ZeusVI]

Unless the adhesive used is faulty, it is indication of one of several things.

Moisture/humidity - usually on paper cone/foam surround speakers unlike the kappa

Temperature extremes - causing premature failure of adhesive.

Enclosure design - incorrect airspace or air resistance due to tuning, most likely in conjunction with pwering the sub full on,to cause pressure buildup in the retractingmotion of the sub, forcing the pressure tobe handled by the surround, which can bulge alittle,unlike the cone. The bulging causes stress on the glue joint.

No biggie, look to see if the glue was insufficiently applied at the point of breach. Check to see if it pulls off easily around the cone. Is there material still glued to the glue where it broke off? Those ???'s tell you if it was poor gluing or weak glue, ad if te last ??? is yes, probably it is the enclosure.

[KeithNguyen]

Okay, from your post the signs are pointing to either heat or enclosure design.

When I checked the sub, it was quite warm, not hot. I'm definitely not over powering it... Would I normally be alarmed? No, but just for the record, it was warm to the touch.

The enclosure with the sub installed is .51 (ft ^3) with the larger variable Q magnet, and with out the sub its mid .60 (ft ^3). Now I'm assuming you're supposed to deduct the basket displacement when following the charts for enclosures in the owner’s manual. Any way, even with those specs, I'm in the middle of the acceptable enclosure volume specs. The enclosure for this sub can actually go down to .3 with the larger variable Q magnet according to the manufacturer.

So, I don't know what to think. I feel like I should be fine with the setup I have now, but I’m considering going with the smaller variable Q magnet since the air pressure is the only thing I could possibly think of. =T

Any more thoughts?

Originally Posted by ZeusVI

Unless the adhesive used is faulty, it is indication of one of several things.

Moisture/humidity - usually on paper cone/foam surround speakers unlike the kappa

Temperature extremes - causing premature failure of adhesive.

Enclosure design - incorrect airspace or air resistance due to tuning, most likely in conjunction with pwering the sub full on,to cause pressure buildup in the retractingmotion of the sub, forcing the pressure tobe handled by the surround, which can bulge alittle,unlike the cone. The bulging causes stress on the glue joint.

No biggie, look to see if the glue was insufficiently applied at the point of breach. Check to see if it pulls off easily around the cone. Is there material still glued to the glue where it broke off? Those ???'s tell you if it was poor gluing or weak glue, ad if te last ??? is yes, probably it is the enclosure.

[ZeusVI]

Excessive heat usually is from a direct light/heat source. Hot hatch, etc, plus some over powering.
Is it a sealed enclosure?
A 1000 watt setup can make some warmth, how much juice you throwin at it?

[Jp-kustomz]

damn that blows

its usually from heat or poor construction
cheaper brand will have that tendency or to much air space or flex

[KeithNguyen]

Originally Posted by ZeusVI

Excessive heat usually is from a direct light/heat source. Hot hatch, etc, plus some over powering.
Is it a sealed enclosure?
A 1000 watt setup can make some warmth, how much juice you throwin at it?

Hmm, again it wasn’t hot to the point I’d be alarmed. I’ve had this same sub in another enclosure get this warm. I never had a problem. Also I doubt I’m over powering it as it’s turned down to match my system. I’m somewhat paranoid about that.

I’m throwing 500W at 8 ohms at the sub. The Infinity sub woofer is rated at 400w RMS, 1600w peak and should be able to take a beating.

Originally Posted by Jp-kustomz

damn that blows

its usually from heat or poor construction
cheaper brand will have that tendency or to much air space or flex

Damn… Well I wouldn’t consider the Infinity sub a cheap brand. And what do you mean by too much air space? Do you mean enclosure air space? Wouldn’t too little enclosure air space be bad?

[Jp-kustomz]

i meants to big of an enclosure and it causes it to flex more than it can handle even if its under powered it will reduce the rms by half and ultimately do what u have

[ZeusVI]

Infinity isnta 'cheap' brand...lolz...theymake good mid-level product. I hv had several sets of their Hi's, the older green Kappa's - never had the prob.

If this happened in the same enclosure twice....then we know the problem

[KeithNguyen]

Originally Posted by Jp-kustomz

i meants to big of an enclosure and it causes it to flex more than it can handle even if its under powered it will reduce the rms by half and ultimately do what u have

I’m sorry, but I am lost about what you’re trying to say… Are you saying if the enclosure is too big, then it would cause flex in the subwoofer and cause the surround to separate? I would think a smaller enclosure would cause more flex, but I could be wrong. Any way, my enclosure is right in the middle of Infinity’s recommended enclosure specs. So I don’t know what to think…

Originally Posted by ZeusVI

Infinity isnta 'cheap' brand...lolz...theymake good mid-level product. I hv had several sets of their Hi's, the older green Kappa's - never had the prob.

If this happened in the same enclosure twice....then we know the problem

I agree, Infinity isn’t a cheap brand. It’s up there especially with their research. I like Infinity, don’t get me wrong. I’m just having bad luck with this particular sub. It’s a great sub, but I need to figure out what’s wrong.

Well, it hasn’t happened in the same enclosure, it’s happen in two enclosures that are similar in the aspect that they’re on the small side. You’re right though, if this happens in this exact enclosure again, I will probably Build a new one with more air volume.

[jonnyv713]

Couldn't it be the enclosure for sure, from over excursion due to the small sealed box?

[KeithNguyen]

Originally Posted by jonnyv713

Couldn't it be the enclosure for sure, from over excursion due to the small sealed box?

I would think so, however remember i'm still within enclsure specs according to the manufacturer suggested volumes. I can't explain how the subwoofer could fail if I'm within specs...

[Jp-kustomz]

if its in a sealed box then thats wat it is for sure either way big or small its just to much pressure

[KeithNguyen]

Originally Posted by Jp-kustomz

if its in a sealed box then thats wat it is for sure either way big or small its just to much pressure

Thanks for the input. I still can't enbrace that thought 100%, but I have no other idea. I'm going to put the smaller Q magnet in so it doesn’t have maximum motor force...

[odieoverclock@yahoo.com]

I have installed Infinity subs for 10+ years, and have never know them to have a glue problem. I have never heard of a Kappa Perfect Glue failure, so I would say "Bad run of the speaker" or "local humidity levels". Harmon makes a great product, and should stand behind it. You can fix glue failure simply by using some Rubber Cement, and letting both surfaces get tacky b4 attaching surface's. I have found the Perfect line to lend itself to a Ported enclosure defying all spec's. The Original Perfect series was one of the best sounding subs I have ever heard just sitting on the floor with no enclosure. The only failures I have seen with the perfects are crushed voice coils due to over excursion, and a light fragile vc's.

[KeithNguyen]

Originally Posted by odieoverclock@yahoo.com

I have installed Infinity subs for 10+ years, and have never know them to have a glue problem. I have never heard of a Kappa Perfect Glue failure, so I would say "Bad run of the speaker" or "local humidity levels". Harmon makes a great product, and should stand behind it. You can fix glue failure simply by using some Rubber Cement, and letting both surfaces get tacky b4 attaching surface's. I have found the Perfect line to lend itself to a Ported enclosure defying all spec's. The Original Perfect series was one of the best sounding subs I have ever heard just sitting on the floor with no enclosure. The only failures I have seen with the perfects are crushed voice coils due to over excursion, and a light fragile vc's.

Thanks, I agree with you that Harman makes a great product. They’re replacing the sub woofer no questions asked so a DIY repair isn’t necessary. They’ve always taken care of me, i.e. another one of my Kappa Perfect subwoofer’s tinsel lead broke, but Harmon replaced it under warranty.

So you think it was just a defective subwoofer huh? Do you think using the Mid Q magnet in a .51 cubic ft. sealed enclosure is fine? It sounds great and I’d rather use this magnet than go down to the low Q magnet. Please advise….