2234 Butyl Surrounds from Japan

[4313B]

Yeah, the rubber surround played hell on the crossover frequency. It was pretty goofy actually. There was a way to get rid of it with a very narrow notch filter but the notch filter was too darn expensive. Going active solved the entire problem.

[srm51555]

Man, they are just 2234s, not some rare and irreplaceable masterpieces. Recone kits are still available. You make it sound like he painted a butyl moustache on the Mona Lisa. JBL is moving away from foam surrounds in favor of rubber, I'm not sure any of their new production designs still use foam. He clearly stated it was an experiment, and he certainly has the skill and resources to perform an inexpensive experiment on some extremely common drivers.

What he said

This was meant to just share some discovery, at my expense.

Thanks for sharing, unfortunately for me I decided last week I was done learning anything new . But honestly, this is how we learn and grow as a forum community.

Thanks,
Scott

[Ian Mackenzie]

I will be barking up my 2216's on the weekend.

Cloth surrounds and cloth ears must work...lol

[Ian Mackenzie]

Some light humour.

Apparently a cloth surround copes better with significant DC across the speaker!

[mech986]

Hang on to the mass rings.

any pics of the completed drivers? And how do they sound in the cabinets?

[1audiohack]

Hi Mech!

They sound indistinguishable from the originals up loud or soft.

This picture shows the worst reveal of the surround and foam gasket where the gasket is pulled back by the clamp. This is how they were. I re-attached the gaskets to in their original positions.

I also cut all the dust caps off and used the JBL alignment sleeve while replacing the surrounds hence the darker cap color.

I don't know if I will just leave them as is or re-cone them. The fact that they are not original does bother me.

If the roll was accurate I think I would leave them. In the end, these do work just fine. I consider the experiment a success.

All the best,
Barry.

[mech986]

Nice, they do look fine at least at first glance, and if they sound similar, then perhaps there's little discernible difference, at least in this application.

As for reconing them, how about swapping them for other frames? I've got a number of 2235H and 2231 to 2235H frames that would need reconing anyway. Seems a shame to replace already functioning cones/voice coils with new if they are working fine.

[Mr. Widget]

I also cut all the dust caps off and...

The glue job on that dust cap is your work? It looks damned fine.

Nice job!


Widget

[1audiohack]

Nice, they do look fine at least at first glance, and if they sound similar, then perhaps there's little discernible difference, at least in this application.

As for reconing them, how about swapping them for other frames? I've got a number of 2235H and 2231 to 2235H frames that would need reconing anyway. Seems a shame to replace already functioning cones/voice coils with new if they are working fine.

I agree. The baskets are original to these boxes and that means a lot to me. I could try to save the kits but,,, well I don't know if it is worth the time.

The second lesson I learned is that if the proper re-cone kit is available and you value your time, just re-cone!

If the new surrounds looked exactly proper I would be done, but it bugs me, just a little.

Barry.

[1audiohack]

The glue job on that dust cap is your work? It looks damned fine.

Nice job!

Widget

It is thank you!

Some years ago I paid Edgewound a half a days shop rate for an education. There isn't much one can't figure out on ones own if they put their mind to it but a good teacher saves you time.

My technique has evolved a bit over time. LOCTITE #410 is the glue used with LOCTITE #712 accelerator applied FIRST! The 712 lasts only about 30 seconds so the 410 application has to be accomplished in fairly short order. The felt is inert and will not kick the 410 and if you apply the accelerator on top of the 410 you get a rougher surface, which I personally don't care for.

The reason for the long answer is that I intended on this thread being somewhat educational to anyone going down this road.

Thanks again W!

All the best,
Barry.

[mech986]

Hey barry,

thanks for the reply. If you do decide to recone, and you could save the old cone/spider/coils without major damage, I'd love a shot at reusing them or at least using them for practice on my frames. Let me know if there's a way to work that out. I could try to make it worth your while to save them.

Good Luck with whatever you decide.

Bart

[pos]

Very nice job Barry!

Have you tried measuring them gain after some aggressive break-in in an effort to lower Fs?

If the new surrounds looked exactly proper I would be done, but it bugs me, just a little.

They look fantastic, you should keep them.
Consider this as a personal improvement exercise: learn to let go

[1audiohack]

Hi Thomas!

I have not re-measured them yet.

It's hard to be mean to them, they get loud so fast so easily. I am currently driving them with one of the M2 project amps (I-TECH 5000 HD) and I can't even get the -20dB LED to ever even flicker before I am ready to run.

You are probably right, I should just leave them alone. I might be able to talk myself into it.

Hi Bart!

If I cut them out I will definitely try to save them for you.

All the best!

Barry.

[JuniorJBL]

I'm with widget! Are you a machine Barry?

Excellent work my friend!

[pos]

By the way, what is the status of the C8R2235?