Need guidance on repair / recone of JBL 2245H woofers.

[Ohighway]

Hey all.

I bought a Danley Contrabass subwoofer yesterday. While at the seller's house, he offered me a pair of JBL 2245H woofers for no cost. Both are messed up in the voice coil area and the surrounds are toast.

The cones themselves are undamaged. Can the cones be re-used if I can find new voice coils, spiders, surrounds and dust caps? Is it cost-effective to go that route?

Alternately I see recone kits for these woofers. If I go that route would it be better to buy a kit that has cone, voice coil and spider already assembled? Or go for a kit where all those pieces have not yet been assembled?

Any thoughts? Any and all information regarding these woofers, their repair, etc. welcome!! Thx.....

 

[MissionX]

@GordonW reconed mine. He's a master and I'm pretty sure could reuse your original cones if requested. If you do it, take measurements and pictures before you disassemble if you're new to it, so you can mount the voice coil properly. SimplySpeakers has a Youtube video on a JBL recone. I don't think all JBL kits are created equal, either. If I remember correctly, there is a fella named Ken on AK that has OE or close to OE cones. Not sure if that name is correct. You would like the drop-ins.

 

[grey]

I would trust Ken or Gordon to work on them. There are a few of them over here and I would want them to sound just as they are for another 10-20 years. A coil, spider, surround only can be done. I can recall a conversation of aftermarket coils coming under scrutiny. Then there is still a question in my mind of having the correct spider/surround compliance.

Congrats on finding the contrabass. Still keeping an eye for one to fill in the sub 30Hz range just for fun. Or I could have cabinets built to run the 2245 down to 20Hz.

 

[EarlK]

If you're lucky the Voice Coils for those 2, 2245's might still be good.

I'd recommend releasing the spider that's still holding the assemblies in place ( acetone should work ). Apply a little to test an inch long spot.

The foam plug behind the dust-cap has likely disintegrated by now, with the particles migrating to the voice-coil and gap. This will have the effect of simulating a burnt VC ( or even causing one ).

If the coil isn't burnt ( bubbled, etc ) , install some new surrounds and proceed to ask about reconing .

 

[Ohighway]

Can anyone tell in the picture of the back that I posted above if that's the correct original JBL cone or a replacement?

 

[EarlK]

The original cone for the 2245 model has a plastic coating applied to onto the back of the paper cone.

 

[grey]

There was three or four versions of oem cones. I can't find the thread I was looking for that has them all together. Some of the aftermarket stuff also has aquaplas applied to the back.

I have some units in need of repair as well. One of them is definitely an oem cone that looks good, but it flexes like a muffin cup. All of the spiders have cratered under the weight of that heavy cone. I can agree that it's worth trying to save an oem cone & coil in good condition.

A couple of links with pics that may help:
https://www.audioheritage.org/vbulletin/showthread.php?20292-2245H-recone-done-right
https://www.audioheritage.org/vbulletin/showthread.php?8787-jbl-2245-H

 

[MissionX]

Something you may or may not care about is that you can't drive these to hip-hop type levels. I listen to rock from the 60s on up and they have their limitations. I have overdriven them when I first got them with an old Crown amp I use to power them. So long as you stay within their limits, they are good.

 

[MissionX]

Can anyone tell in the picture of the back that I posted above if that's the correct original JBL cone or a replacement?

If you take a picture of all the numbers on the cones, the gurus will know.

 

[BMWCCA]

Something you may or may not care about is that you can't drive these to hip-hop type levels. I listen to rock from the 60s on up and they have their limitations. I have overdriven them when I first got them with an old Crown amp I use to power them. So long as you stay within their limits, they are good.

Haven't experienced any limits in the 15-years I've had mine. And you don't hear about this issue in the original iMax system where perhaps a dozen of these were used as the subs in immersive theater installations such as the Smithsonian Air and Space museum. I have no first-hand experience with overdriving them but would love to hear something more detailed beyond overdriven with "and old Crown amp". I've used mine on DC300A-II and PS-400 where their original owner used Haflers.

 

[MissionX]

It's a CP660.

 

[Ohighway]

If you take a picture of all the numbers on the cones, the gurus will know.

I'll go out in the van and take some pictures of the cones and post them. Also see if the voice coils still have continuity.

 

[elitopus]

I have a pair of 2242 that Gordon custom reconed for me. With specs similar to the 2245, except mine have cloth accordion surrounds.

I have a pair of E155 that had the problem Earl described. Both of them had so much junk in the VC gap that they were locked up. I was able to take them apart and get them working again.

 

[grey]

I have a pair of E155 that had the problem Earl described. Both of them had so much junk in the VC gap that they were locked up. I was able to take them apart and get them working again.

What is the process? Have an E145 that may be locked like that.

 

[elitopus]

What is the process? Have an E145 that may be locked like that.

If you’re lucky you can just remove the dust cap and vacuum the stuff out with a shop vac. But otherwise you need to take the cone out like Earl describes. If you’re lucky you can reuse all the parts, including the surrounds.

I’d start by cutting the dust cap to make sure the magnet hasn’t shifted. I had a 2225 like that.

 

[Ohighway]

So here's a look at what I have. Magnets look centered. Cones themselves look good however I see no alpha/numeric markings anywhere on cones. Both voice coils look scraped and at least one has a broken wire. Surrounds and spiders are shot.

I'm wondering if a pre-assembled cone, voice coil, spider, surround assembly might be the best way to go here?

 

[elitopus]

https://reconekits.com/jbl2245h8ohmreconekit.aspx

 

[hjames]

Rather than ship them to Georgia, why not use a local resource who is a JBL pro and has huge experience.
He did great work with the Philips woofers for the Heathkit speakers I had.

Scavenger Sound Inc
1011 Rose Anne Rd
Glen Burnie, MD.
(410) 761-1072

John Harding - oldmics@yahoo.com

 

[EarlK]

Thanks for the pics.

The internal foam filters look mostly intact >> so that theory of them binding the VC in the gap is "out-the-window" !!

The VoiceCoil damage looks to be caused by rubbing >> likely caused by running the woofers with failing surrounds for too long.

The cones look original and appear to be plasticized ( that's the aquaplas ).

John Harding might be able to re-use those in a rebuild.

Make note of total cone-assembly weight ( include the full spider ) should you decide to try a recone yourself.

The ( assembly ) weight roughly equates to Mmd ( found within some ) Ts Parameters.
- Mms ( the more commonly found stat ) is "Mmd + air-load" .
- You can approximate airload by reading some spec sheets ftom a few Italian driver makers of 18's ( since some include both Mmd + Mms in their Ts parameters ).
- FaitalPro lists both Mmd + Mms in their spec sheets.
- A brief review of about 5 models shows the airloads ( averages out to ) @ 48 grams .

The Mms of the JBL 2245H is given as @ 185 grams. So subtract an airload of 48 grams and you are looking to buy a kit where the static cone assembly weighs 135 to 140 grams.

 

[elitopus]

I was thinking the OP was considering doing the recone himself