4642a driver replacement

[Jon Dent]

Hi. We blew a cone in our 4642a sub (see the post about Voyagers) and we're looking to replace the driver itself rather than shell out $$ for a new sub. The 2241H driver is old and a bit hard to come by, but I've seen a few suggest that the 2268HPL is a valid alternative (in addition to being newer and cheaper). Does anyone have any experience with this kind of swap? Is there another alternative for the old 2241H driver? I'm new at this

[Kenneth Wuepper]

Why do you not consider the re-cone solution to repair of drivers?

[Carsten Kurz]

Yup. This is a very expensive driver. Within the US, there should be many companies offering reconing services. The parts are usually genuine JBL, so there is nothing to worry about.

[Marcel Birgelen]

Reconing should be entirely possible, but do yourself a favor and recone both drivers. If one already failed, the other one is probably just weeks or months away from suffering the same fate and your speaker will be more balanced if you give them both a refurb.

[Jon Dent]

Hadn't considered re coning but I'm watching YouTube on it now. Seems doable.

[Steve Guttag]

The 2241H is definitely a recone candidate. Furthermore, it should not be hard to obtain new. The 2241HPL may not be available as an over-the-counter driver but it would be available as a service part. I definitely would not mix and match a 2241 with a 2268. They are different motors, different displacements.

The cheapest/best solution is recone the failed driver. Second best solution, buy a replacement driver of the same make/model. If you want more out of that box you could buy a pair of 2242HPL drivers (its a better driver and more suited to subwoofer duty) but that is probably more than you want to spend.

[Marcel Birgelen]

Is there actually a difference between the 2241H and 2241HPL? The 2241HPL should be the "OEM" version of the 2241H, so the only difference should be the lack of any visible JBL branding on the PL version.

[Steve Guttag]

The "PL" versions (Private Label) typically have a black color around the circumference of the driver. Non-PL versions can have a brushed "silver" finish...which may look nice in a PA system...not so in a cinema system. So, when given the option, the PL versions are preferred in cinema.

[Jon Dent]

We decided to go with the recone option as we just spent a wad of cash on other theater upgrades so our budget is pretty thin right now. Steve, as you mentioned the 2241 isn't exactly hard to find (I didn't phrase that correctly above) but it's not cheap either ($500 a piece at the low end). So we'll work our way up the chain... If the recone doesn't work then we'll save up for a new driver

Thanks for the help everyone.

[Kieran Hall]

Not sure if I'm reading your previous post right that you're attempting the recone yourself? If so you want to make absolutely sure you avoid any non-original JBL recone kits (I think at one point JBL didn't 'officially' sell their recone kits to the public but not sure if that's still true). They're not great at the best of times but it's even more important in a twin driver speaker as they won't match.

[Jon Dent]

Well the situation got more interesting.

I pulled up the screen today and inspected the sub. It looked fine and the driver didn't have any visible damage or sounds when moved. I fired up a custom trailer that has strong 30-50Hz content and had previously produced the 'blown speaker' sound, and I heard nothing but solid bass. I turned up the volume to our usual level and ran it again. Still sounded just fine. Ran through our entire trailer reel and the first parts of Wrath of Man (which contains some moderately strong LFE transients) and it sounded just fine. So now we're wondering if it's the amplifier instead

[Marco Giustini]

if the screen is VERY close to the driver, it could be the screen itself. People may laugh at this statement but I had that before: a subwoofer was clearly sounding as "blown" but once the screen was loosened and moved away, the noise would stop.

Surely, it could have been the amplifier clipping or the driver bottoming if the system is not properly dimensioned for the room.

[Carsten Kurz]

Can you still run 'Voyagers'?

[Steve Guttag]

You have two drivers in there so make sure both drivers are playing well. I'd recommend doing a frequency sweep on each driver. This does presume that you have a good amplifier to do the sweep as you should feed a 10V signal from 20Hz to 1.2KHz. That driver should not rattle/buzz during the sweep. At 10V, out of the cabinet, it will get VERY loud as the frequency goes up. Also, since it vents from the rear, it can't be set directly on a surface or it will block its vents.

In the cabinet you can also do the same sweep but the bass is also going to be loud. I'd verify that both drivers are connected using either an ohm meter (you're looking for about 2.5Ω or thereabouts, no more than 5Ω, if both drivers are connected. I also use a continuity tester if it has an incandescent lamp (LED versions are no good). With a continuity tester, a click with a bright light = 4Ω. Click with a dim light = 8Ω, Click with no light = 16Ω. That sort of continuity tester is also good for checking switches, by the way. It will let you "see" when there is contact resistance building up on RoHS approved switches/contacts.

As others have indicated, JBL does not approve the selling of recone kits as a repair part. Only authorized recone centers are supposed to be able to supply them as part of the recone service (used as a part with the service). This not to say you can't find them out there on eBay and a couple of speaker parts supply companies.

[Marcel Birgelen]

Just something that comes to mind: Have you tried playing the problematic content with only the amps for the sub switched on, just to check it's nothing else that causes the "blown speaker sound" you mentioned?