It pains me to admit I efffed up, but I want to spread the word to others here so they don't make the same mistake.
I added weight to my Emimence KL3012HOs to get the TSP specs and efficiency where I wanted them so I could cheap out and not order the C0RRECT drivers to begin with. The woofers were going to be used as the LF in a 2.5 way along with the KL3012CX coax drivers. Well, against my instincts I used Neoprene loaded adhesive (aka 3m weather strip adhesive) as it stays flexible and can be gradually added to obtain exact weight. YES, I SHOULD HAVE USED EPOXY, but only had the grey JB weld on hand, which shouldn't be used on the moving assembly of a speaker due to it containing iron particals as filler. Anyways, I embedded a coil of 12 awg copper wire (loop not closed to avoid a shorted turn) so the added weight came to 13 grams. Everything went well and I got the weight bang on. I've used this technique a few times before with success, but with liquid glue, not this thicker consistency stuff.
Well, now the part where I found out that I screwed up - I put the drivers on the sine wave gen and swept with 16V. The first one was perfecf, but low and behold I had a noticeable resonance spike on the other in the FR curve at 1 k. This turned out to be the copper loop buzzing on a spot where apparently the glue didn't get or stay in between the copper and cone. I tried injecting cyano glue and retesting, but the buzz was still there. I then tried cutting a slit into the glue and adding more cyano, but it was pointless. The other driver is perfect without any issues.
The moral of this story is ONLY USE EPOXY to glue anything on the moving assembly of a speaker (poly cones excluded). Otherwise it will end up buzzing or making other undesirable strange noises which could only be detected by THD measurements. Now I'm stuck with 2 paperweights to the tune of over $500. I feel like a complete idiot.
On the plus side (if there is one), I put the one driver on the sine gen and ran the driver at 40V free air around 100hz. Couldn't kill the thing running it there over 5 min which is a testament to Eminence durability. However, the suspension was so stressed at that point it was worn out and felt like a woofer that played for several years at full power in a dive bar. The KL3012HO is not a good dedicated LF driver, but rather a midbass. It should not be used over its small xmax limit.
Now I'm stuck ordering the correct drivers i should have to begin with (KL3012LFs). I may recone these others but Eminence doesn't usually sell recone kits for these outright. I may have to ship these to Eminence. Oh well...
I added weight to my Emimence KL3012HOs to get the TSP specs and efficiency where I wanted them so I could cheap out and not order the C0RRECT drivers to begin with. The woofers were going to be used as the LF in a 2.5 way along with the KL3012CX coax drivers. Well, against my instincts I used Neoprene loaded adhesive (aka 3m weather strip adhesive) as it stays flexible and can be gradually added to obtain exact weight. YES, I SHOULD HAVE USED EPOXY, but only had the grey JB weld on hand, which shouldn't be used on the moving assembly of a speaker due to it containing iron particals as filler. Anyways, I embedded a coil of 12 awg copper wire (loop not closed to avoid a shorted turn) so the added weight came to 13 grams. Everything went well and I got the weight bang on. I've used this technique a few times before with success, but with liquid glue, not this thicker consistency stuff.
Well, now the part where I found out that I screwed up - I put the drivers on the sine wave gen and swept with 16V. The first one was perfecf, but low and behold I had a noticeable resonance spike on the other in the FR curve at 1 k. This turned out to be the copper loop buzzing on a spot where apparently the glue didn't get or stay in between the copper and cone. I tried injecting cyano glue and retesting, but the buzz was still there. I then tried cutting a slit into the glue and adding more cyano, but it was pointless. The other driver is perfect without any issues.
The moral of this story is ONLY USE EPOXY to glue anything on the moving assembly of a speaker (poly cones excluded). Otherwise it will end up buzzing or making other undesirable strange noises which could only be detected by THD measurements. Now I'm stuck with 2 paperweights to the tune of over $500. I feel like a complete idiot.
On the plus side (if there is one), I put the one driver on the sine gen and ran the driver at 40V free air around 100hz. Couldn't kill the thing running it there over 5 min which is a testament to Eminence durability. However, the suspension was so stressed at that point it was worn out and felt like a woofer that played for several years at full power in a dive bar. The KL3012HO is not a good dedicated LF driver, but rather a midbass. It should not be used over its small xmax limit.
Now I'm stuck ordering the correct drivers i should have to begin with (KL3012LFs). I may recone these others but Eminence doesn't usually sell recone kits for these outright. I may have to ship these to Eminence. Oh well...
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Costly. 🙁
But you find that normal two part epoxy stays on a paper cone OK even with all the shaking going on?
But you find that normal two part epoxy stays on a paper cone OK even with all the shaking going on?
Found one dealer that has a recone kit in his program but only b2b?
https://mcbrideloudspeaker.com/Eminence-KAPPALITE-3012HOARK.html
Sorry for your loss
https://mcbrideloudspeaker.com/Eminence-KAPPALITE-3012HOARK.html
Sorry for your loss
McBride lists a recone kit, but no price. https://mcbrideloudspeaker.com/Eminence-KAPPALITE-3012HOARK.html
Epoxy works very well. Never had it come off or partially separate.
Dissolving all that mess is going to make it look like crap. I've already moved on from these. They won't be even close to what they were before even if I take more time to do something that is a waste. The glue did remove most of the peak at 2.5-3k, which comes mainly from the dust cap edge breaking up on this driver.
Dissolving all that mess is going to make it look like crap. I've already moved on from these. They won't be even close to what they were before even if I take more time to do something that is a waste. The glue did remove most of the peak at 2.5-3k, which comes mainly from the dust cap edge breaking up on this driver.
Yeah, I saw that listing on their site. Eminence hates selling parts unless its a diaphragm for a CD. I was going to recone it with the LF model guts, but realized the magnet yoke is different from the HO model. The double roll surround doesn't do well for longer cone excursions.
Pour about 100 ml of xylol into the cone and cover the driver with something non-permeable (large enough PP cutting board, glass sheet, etc). Optionally stretch wrap the whole thing. After an hour or two the glue should be soft enough to gently scrap avay with a small spatula or not-so-sharp knife. Add more xylol if necessary.
Most adhesives yield to xylol, otherwise try combination solvent of toluene+xylol+ethyl acetate.
Most adhesives yield to xylol, otherwise try combination solvent of toluene+xylol+ethyl acetate.
I thought about that, but the paper cone is thirsty on this driver and will probably soak up some of the solvent. I do appreciate the advice and It probably can't hurt trying, but at this point I'm not wasting any more time. I'm going to recone them to use as midbass drivers in another project.
The other issue is the Kapton VC former this woofer uses, which I'm not fond of. I'd rather have a fiberglass former in there which sounds cleaner in the mids at high output levels. That.would also give me the chance to use different suspension parts as well. Not sure what I want to do right now.
The other issue is the Kapton VC former this woofer uses, which I'm not fond of. I'd rather have a fiberglass former in there which sounds cleaner in the mids at high output levels. That.would also give me the chance to use different suspension parts as well. Not sure what I want to do right now.
Interesting. I’ve used silicone glue before and didn’t have any buzzing problems. Sounds like you were polishing a poop, should have bought the shiny rock in the first place. Seems to be the story of my life. 😉
I usually don't bother with cheap drivers or ones that are square pegs in round holes. The only reason I bothered doing what I did is the TSPs and efficiency were favorable to be pushed in the right direction by adding weight. Since this is a passive xover build, it would have worked out, but in retrospect the practical xmax of the driver wouldn't have been enough to offset the hassle. Part of that issue is the double roll surround and its hard limit on excursion compared to the typical multiple pleated accordian style found on most pro drivers.
The KL3012LFs have a 37 hz Fs as opposed to 52 hz on the HOs and alot more xmax. I'm looking for LF extension flat to low 40s in a ported 3 cu ft box to be worth the hassle for me being its a passive build. I learned my lesson on this one not to risk an expensive new driver to save money. Even if it would have worked out getting the specs where they were, the xmax would have not been enough to get the expected LF output without using subs.
The KL3012LFs have a 37 hz Fs as opposed to 52 hz on the HOs and alot more xmax. I'm looking for LF extension flat to low 40s in a ported 3 cu ft box to be worth the hassle for me being its a passive build. I learned my lesson on this one not to risk an expensive new driver to save money. Even if it would have worked out getting the specs where they were, the xmax would have not been enough to get the expected LF output without using subs.
The silicone route works too, but its hard to get a clean look with, plus its a bit too flexible and robs upper end FR if the driver is used full range. The problem I had was not enough glue between the cone surface. That would be problematic with any flexible adhesive. Epoxy still is preferred IMO in terms of durability. When reconing a driver, I always use epoxy to glue anything that moves rigidly with the cone. Everything else gets neoprene contact adhesive ie the black sticky stuff.
Again, appreciate the info and I'd do what you suggest if it wasn't for having to do this indoors and deal with the fumes. All those solvents are very nasty for your health. I get very sick when exposed to them without a ton of ventilation.
Hi Profiguy,
If just to add weigth, whatever for T&S measurement or to last, I wonder if little cord of UHU Patafix around the dust cap (and black colore exists) would not be easier to remove if needed. Plus if between the dust cap and the cone transition, it could also be usefull for reflexion damping, smoothing purpose ?
Also a round natural sisal twine holded with some spot of Patafix around the dustcap sat 12h00/15h00/-18h00/21h00 : https://www.les-fils-du-temps.com/ficelle-fine-c6x32188989 .... dirt diy but easy to remove.
Bastanis loudspeaker use round pad felt around the dust caps : easy removable if you do not push too strong on the double tape under it !
If just to add weigth, whatever for T&S measurement or to last, I wonder if little cord of UHU Patafix around the dust cap (and black colore exists) would not be easier to remove if needed. Plus if between the dust cap and the cone transition, it could also be usefull for reflexion damping, smoothing purpose ?
Also a round natural sisal twine holded with some spot of Patafix around the dustcap sat 12h00/15h00/-18h00/21h00 : https://www.les-fils-du-temps.com/ficelle-fine-c6x32188989 .... dirt diy but easy to remove.
Bastanis loudspeaker use round pad felt around the dust caps : easy removable if you do not push too strong on the double tape under it !
Westrex modified one of their 2080 ( Altec 515 ) woofers for a home HiFi product by adding a brass ring to lower it's Fs ( glued around the dustcap//cone joint ) .
They called it the 2080E. This info comes from LHF ( poster AndyWin I believe ).
Here's the pic;
IOW, the concept has historical precedent and validity ( IMO ).
🙂
They called it the 2080E. This info comes from LHF ( poster AndyWin I believe ).
Here's the pic;
IOW, the concept has historical precedent and validity ( IMO ).
🙂
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Use some old soldering iron. Slowly press the hot tip to the glue and it will burn it little by little. Just don't touch the paper. Slowly set free the ring. I did that lots of times.
Be sure to try that outside and with fan blowing the fumes away from you because burning glue smells awful.
Be sure to try that outside and with fan blowing the fumes away from you because burning glue smells awful.
Funny you post this... it was exactly what I was copying to do. They also have a gap in the ring and used a SOLID piece of wire, NOT BRAIDED, which can vibrate inside its own strands. I'm sure they also used better adhesive too which should have been stronger. For those who still are skeptical, read up on speaker reconing and why most (if not all I've ever seen) pro audio drivers use epoxy anywhere in parts that are a part of the moving mass. I'm sure there are hifi drivers that don't use epoxy at the spider/cone/VC junction for various acoustical dampening purposes, but these drivers dont get pushed very hard. I used to recone speakers for a living and should have known better than to use contact adhesive in that area.
You could remove the wire, and add a solid ring with an adhesive, then apply a larger diameter dustcap to fix the cosmetics. Way back in the day, a Maelstrom 18" driver had a large diameter nut added to increase the moving mass, and a couple of dustcaps stacked to cover it.