Reconing 15" bass drivers on JBL 4350A's: Need a pro shop

[j20056]

I have a pair of JBL 4350A's and I had those re-coned by a JBL service center (which I forget where) back about 15-20 years ago. Now, the rubber rim connecting the cones to the frame is frayed and coming apart and it is time to get all 4 of them fixed. I don't see any damage or wear and tear on the membranes themselves (they are pretty thick), and they seem to work OK as far as the electric circuit. The increasingly noticeable sound is distortion (boinking type of sound from woofers) but I don't think the coils or magnets have any issues although maybe worth an inspection when being fixed.
So the question is where am I supposed to do this since I do not remember where I did it 20 years ago.
Any recommendation of a good place is appreciated.

PH

[Robh3606]

Can you post a picture? Do you have white cones or grey? Stop playing them if you damage the coils it will severely limit your options dependlng on what bass drivers you have in them.

Rob

[gdmoore28]

Where are you located? Great Plains Audio in Oklahoma City is a first rate Altec/JBL service center. Don't bother trying to email them - calling is the only way you will contact them. Talk to Bill.

Great Plains Audio™
7127 Northwest Third St.
Oklahoma City, Oklahoma 73127
Phone/Fax: 405-789-0221

[speakerdave]

Where are you? Local service is best if available because shipping big heavy woofers is expensive and careful, informed packing is required.

Based on your description of what you are hearing, you should not be using those speakers anymore as they are, since the surround helps hold the voice coil in place, and if it can tip it will rub and that's good-bye.

JBL sells only complete new recone kits, but there are replacement surrounds available which work well. On the other hand, if you are OK with the expense, total recone is best.

The ideal would be an authorized JBL shop (one which follows JBL instructions) which also has the equipment for recharging your Alnico magnets. These are not common, because Alnico magnets are no longer common.

Given your location someone here might be able to tell you about a shop near you. If you end up shipping, legacy Altec specialist Great Plains Audio is now servicing JBL, I believe, and they routinely remagnetize Alnico woofers. Check with them; they are in Oklahoma City.

[speakerdave]

Three simultaneous helpful posters.

One more thought implied by Robb--it matters whether you have original type cones or not. Some prefer them. If you have them, and they are salvageable, you should give them up only after considering the differences between them and the JBL-provided 2235h replacement.

[j20056]

I don’t think I should have used the word recone. What is damaged and almost fully unglued now is only the rubber rim connecting the cone to the metal frame. There is no damage to the cones nor the coils. I found an online retailer that sells the rubber replacement parts and they have very detailed instruction videos on how to safely remove and clean the old rubber rims and put new ones. It’s $39 for a pair, including specialized glue. There are more than 25 comments from customers (all 5 stars) who bought the product including 2 that used it for 2231A’s like mine as it is made exactly for series of JBL and UREI 15” drivers including the 2231. So for $78 I think I am going to try this as it appears quite easy to do. Happy to report afterwards once the repair is hopefully successful. URL is below.

https://www.simplyspeakers.com/jbl-s...fsk-15jbl.html

[speakerdave]

I don’t think I should have used the word recone. What is damaged and almost fully unglued now is only the rubber rim connecting the cone to the metal frame. There is no damage to the cones nor the coils. I found an online retailer that sells the rubber replacement parts and they have very detailed instruction videos on how to safely remove and clean the old rubber rims and put new ones. It’s $39 for a pair, including specialized glue. There are more than 25 comments from customers (all 5 stars) who bought the product including 2 that used it for 2231A’s like mine as it is made exactly for series of JBL and UREI 15” drivers including the 2231. So for $78 I think I am going to try this as it appears quite easy to do. Happy to report afterwards once the repair is hopefully successful. URL is below.

https://www.simplyspeakers.com/jbl-s...fsk-15jbl.html

They may be fine (except they seem overpriced), but since you came here and asked I should tell you that we have long used, with consistently good results, foam surrounds from Rick Cobb whose seller moniker on eBay is Looney Tunes.

[j20056]

I wish it showed up first on a google search, although I thought $39 versus the perspective of having to ship heavy 38cm magnets was appealing versus a full outside servicing. Thanks for the feedback though.

[grumpy]

Opinion on

If this is your first re-surround rodeo, I’d strongly suggest you either leave this to a professional that has demonstrated ability and knowledge (not always so easy to determine), or practice on some shit speakers first, before hacking on fairly valuable, no longer available, drivers. It may appear easy, but it’s also easy to make a bit of an unprofessional looking mess. If there is no voice-coil rubbing, the 30hz tone method (vs cutting out the dust caps and using shims) is often sufficient. Inexperienced dust cap glue lines are a dead giveaway of a diy-level job (also reducing the value, down the road).

So...nice speakers, worthy of proper maintenance.

Opinion off.

[Robh3606]

Not sure what videos you have seen but we have a step by step on the site. The suggestion of doing a practice run is not a bad idea. Take your time and you should be fine. If you have any doubts don't.

Rob

http://www.audioheritage.org/vbullet...d-Step-by-step

[rusty jefferson]

What Grumpy said. Not a place to experiment. IMHO.

[Robh3606]

What Grumpy said. Not a place to experiment. IMHO.

Yeah I tend to agree but I have seen some real butcher jobs so if you choose a shop you really need to see their work and specify you want the foams installed on the back of the cones. If you get any grief move on. It just extra work to put them on the back. Real easy to just ignore the sticky glop on the back and leave it there and just drop them on the front.

Rob

[j20056]

Thanks Rob.

As mentioned before, I wish i would have met you earlier but upon watching the online video from the place where I bought the surround rims, they indicate that it has to be glued on the rear side of the membrane, and upon inspection, that is clearly how my existing 2231A's are glued. I hope I won't make a mistake but if you have some extra knowledge that you feel is not mentioned in the online video, I am happy to re-purchase the hardware from you and get your extra knowledge. Obviously, I am not going to worry about an additional moderate cost to get this done right.
Am I really supposed to worry here though?

[grumpy]

It’s mostly in the prep work, like most things. Carefully removing existing gaskets for reuse, cleaning the frame down to metal (access to MEK, a well ventilated space, a lazy susan/turntable) and removing excess glue from the cone without damaging or weakening it, using sufficient glue without being sloppy, cleaning up slop (it happens) with a damp rag right away. Waiting out the recommended drying/centering periods.

Hope it it goes well.

[j20056]

Thanks all. Between your advice and the instruction video , which are 100% correlated, i feel well equipped to do this.