Edit: WOOFER with problems - Forte II

[papashawn]

One of the midrange drivers in my Forte II's is damaged I'm

afraid. It sounds fine at lower volumes, but when I turn up music

fairly loud, I can hear it distort. Also, over the weekend I

replaced the crossovers and noticed an amber colored liquid (with the

consistency of molasses) coming out of the bottom of the midrange

driver. I wiped this off with a rag, but I can't help but think

that this is somehow related to the damaged driver. The first

night I listened to them with the new crossovers installed, I didn't

notice any distortion. Last night I watched an entire Pearl Jam

concert DVD and didn't notice any distortion, but I was listening to

some CD's afterwards, and heard it again. Is it likely that

replacing just the diaphragms will solve my problem? Also, I'm

assuming that I should replace both diaphragms at once to keep things

balanced between the two speakers. If I'm replacing the midrange

diaphragms, should I also replace the ones for the tweeters, or should

I leave them alone if there is no problem with them? Thanks in

advance for your help!

[Frzninvt]

A diaphram replacement will correct the problem, the goo is probably the ferro-fluid that is in the voice coil gap in the magnet structure.

[papashawn]

Is that goo something that could have damaged other parts of the driver, or will I be able to just clean it up when I'm replacing the diaphragm and take care of the problem there? Thanks for the info!

[STL]

A diaphram replacement will correct the problem, the goo is probably the ferro-fluid that is in the voice coil gap in the magnet structure.

Does leaking ferro-fluid automatically mean the driver is bad (forcing a diaphragm replacment)? Maybe horn lens just needs to be

tighten so it's better sandwhiching the diaphragm to the magnet/motor.

[colterphoto1]

ferrofluid looks like used motor oil. Just clean up what you can and call Klipsch for parts- there should be a diaphragm replacement kit. When you get it, dont worry about cleaning out the ferrofluid or adding more, just leave it be and insert new diaphragm. The ferrofluid helps disperse heat a bit, but you cannot buy it in small quantities, so it's ok to just do without.

[STL]

ferrofluid looks like used motor oil. Just clean up what you can and call Klipsch for parts- there should be a diaphragm replacement kit. When you get it, dont worry about cleaning out the ferrofluid or adding more, just leave it be and insert new diaphragm. The ferrofluid helps disperse heat a bit, but you cannot buy it in small quantities, so it's ok to just do without.

Again, does leaking ferrofluid really mean the diaphragm is bad? I've never heard that before...

I know someone (like PartsExpress or Madisound) used to sell small vials of ferrofluid, but I cannot seem to find it on their websites so maybe that's no longer the case.

[jheis]

STL

The short answer is no.

I went through this a while back. While the purpose of ferrofluid is still not entirely clear to me, it is injected into the circular slot in the speaker magnet that the voice coil rides in/is suspended into. As Colter said, the ferrofluid supposedly helps to dispense heat, but some speakers use it - others do not - it doesn't seem to make much, if any, difference either way. The "ferro" component tends to hold it in suspension in the magnet, but since it is kind of an oily liquid and the speaker is vertically oriented, it wants to seep out. It has nothing to do with the diaphragm being good or bad - although if the fasteners holding the diaphragm in place are not tight it would tend to promote leakage because of the poor seal.

Diaphragm failure is usually due to a mechanical failure of the voice coil - such as a burnt or broken wire. The voice coil wires are only about as thick as a strand of human hair.

James

[papashawn]

Thanks for your help guys. I called Klipsch for the replacement diaphragms but needed my serial numbers, so I have to write them down and call again tomorrow. Is this replacement going to be difficult? I know I can replace one from the tweeter, but I'm not sure how different the mid driver is going to be. I'm assuming I'll be disconnecting the wires from the crossover, and taking the horn/driver out of the front of the speaker to do the replacement. Has anyone else ever done this surgery before? I saw a few posts with some instructions for doing this on a cornwall, but didn't have much luck with the forte. Thanks again for your help!

[STL]

papashawn,

On the older speakers it is more complicated to replace the midrange diaphragm, but the Forte II has the H-52H so it's no harder the replacing a tweeter diaphragm. So did the replacements run like $29.84 each?

jheis,

Thanks for clearing that up. That was what I always thoughs too, but the other response implied otherwise.

[papashawn]

STL

The spec sheet for the Forte II on the website says that the midrange driver is a K-61-K. I haven't got a price quote from Klipsh yet, I forgot to bring the serial numbers to work with me today, so I won't be able to call them again until tomorrow. But if the replacement is still the same as with the tweeter, I'll be happy because I've done that before and its simple.

[colterphoto1]

If parts will sell the diaprhagms, it's a fairly easy matter to replace them. If it's complicated we usually don't sell them at retail.

The S/N request is because we have a limited supply of some parts. Customer Service is making an effort to reserve those parts to the owners of real Klipsch speakers and not to sell for hobbyists or experimenters. We're also warding off the sale of imitations by watching the sale of name badge placards.

Thanks,

Michael

[papashawn]

So this is some really bad news. Its not the midrange diaphragm

at all, its the WOOFER! I made sure to listen to really clean and

clear music, turned it way up and stuck my head right next to the

woofer, and sure enough, when the bass hits hard, it sounds really

muffled and sloppy. At lower volumes, this doesn't happen at all,

so its only when the woofer is really moving that I get this

problem. I made sure to listen to the other speaker,and it was

clear at the same volume, nothing muffled or vibrating. Is there

something I can do to remedy this, or am I going to have to replace the

woofer? This is sounding like a much more expensive fix than I

had anticipated.

[STL]

From what you've said, there is really nothing you can to fix it except to replace the woofer. If the other one sounds good and clean then I'd only replace the bad one. I think it's a K-25-K that you need.

[papashawn]

Ok, I've done a lot of reading through the forum about forte woofer

problems, and I think the issue has something to do with the cone

touching the voice coil. I took out the woofer and lightly

pressed in evenly, didn't get and scraping, but when I pressed in

around the perimeter, I had a scraping sound between 9:00 and

4:00. I've reinstalled the woofer turning it 180 degrees to see

if it alleviated the vibrating sound when playing. I also checked the

good woofer. It had the same scraping against the voice coil as

the other, but doesn't make any vibrating sounds while playing. I

reinstalled the good woofer turning it 180 degrees as well. The

best way i can describe the sound is as follows. When the volume

is turned up very loud (almost uncomfortable) and the bass really hits,

it sounds almost as if the cone is not attached to the surround, and

its a flapping/vibrating sound, but only on those really long throws

when the bass hits that hard. The other woofer doesn't have this

problem, and l really don't see or feel any areas where the cone isn't

attached to the surround, and the dust cap is securely attached as

well. Would it be worth it to apply a ring of white speaker glue

around at the surround and the dust cone just to reinforce it?

Since this only happens at such high volumes, its not as big of an

issue as I had originally thought. If it starts to happen at

normal volumes, I'll have to either get the new woofer replacements

from klipsch (the K-28 I believe, since the K-25 is no longer made) or

send them off to be reconed. I've read a lotof good things about

woofer.com and nevisonics. I would definitely prefer to go this

route if the cost were going to be the same as buying new. This

way I could keep the originals.

[WMcD]

Tell us . . . are these something you bought used recently? Could the previous owner have driven them hard? This is to say, when did the problem develop? Did anything happen just before the problem developed?

My first thought was that the mid was driven so hard that the ferro fluid was blasted out of where it resides. That would require a hole in the assembly for it to leak.

Then you mentioned the woofer issue. I started thinking maybe the woofer was driven very hard and this created an extra-ordinary pressure and vacuum in the box, and this leaked into the mid driver to blast out the ferro fluid.

Now you're talking about some floopyness in sound or actual woofer motion. I'm thinking air leak. And the hole through which the ferro fluid escaped still comes to mind.

I would check for an air leak by pushing gently on the woofer or passive, and see if the other moves. If you push in on one, the other should move out, and if you hold the other should stay put for several seconds if not longer. I'd check if the bad and good speakers behave the same way in this respect.

Maybe the bolts holding the mid driver together are loose or something. Did a previous owner mess with this?

Those are my thoughts.

Gil

[papashawn]

I did the test pressing in on the woofer and the passive moved out equally and stayed there for a several seconds, both speakers behaved the same. I don't believe there is an air leak, or at least there isn't any more air leaking that what seems to be normal (as the passive does return to its resting position eventually). I removed the mid driver when I was first investigating this problem, thinking it was the mid and not the woofer at the time, but everything with it seemed to be in fine condition. I reattached the horn to the driver as snugly as possible, and I reinstalled the driver flipped 180 degrees. The mid doesn't sound bad whatsoever. My first impression from sitting on my couch listening was that it was the mid, but upon closer inspection, the mid is fine and only the woofer exhibits the floppy vibrating sound. Luckily it only occurs when the volume is really high, but on some recordings the bass hits hard at lower volumes so it can be more of an issue depending on the recording. Does anyone know how much a recone costs roughly these days?

[DrWho]

Is it the woofer or the passive radiator in the back that's making the flapping sound? Does it sound like a clicking? You might check that the wire leads going between the basket and the diagphragm aren't slapping against the diaphragm.

[Reid]

You could check the spider on the speaker. This is the material that helps control the motion of the speaker and center it over the coil. I have a sub that had a loose spider. I used some super glue to reattach it and it has never bothered again. Look real close and move the cone, it may be hard to see if the spider is loose.

[papashawn]

I've listened very closely to both the woofer and the passive radiator, and it is definitely the woofer making the noise. The best way I can describe it is a flapping sound, almost as if the cone is coming unattached from the surround, even though it is completely attached and has no problems at lower volumes. I checked the wires behind the cone and they seem to be out of the way. They weren't any closer to the cone than on the good woofer, which doesn't make any sound. I took a brief look at the spider, it appeared to be flat when I was looking at it, not sticking up at any parts. I don't know if its loose, I'm not sure where exactly it attaches though. I'll have to take it out and have another look. Was yours loose where it attaches to the cone or to the metal frame? I'll look tonight and see if that's an issue. Thanks for your help!

[Reid]

My spider was loose on the metal frame. Did not notice until I pushed gently on the cone. Super glue fixed the problem, Several light coats all around to attach to the metal. No problems since the fix.