JBL 4412A and 4410A Correct Foam (128H-1 and 127H-1)

[SaturationPt]

I decided to refoam these pairs because unfortunately JBL has discontinued the kits (cone kits).

There are many suppliers of foam kits marketed for both of these, but many are not correct.

The roll on the 127H-1 (10") is 10/16" wide, which I found at Springfield Speaker.
The roll on the 128H-1 (12") is 12/16" wide, which I found at Simply Speakers.

Many others have 9/16" wide rolls marketed for both of these speakers, not sure whether this would limit the excursion unnecessarily but decided not to take the chance.

Hopefully this will help anyone else looking for these and you can avoid ordering several sets to find out as I did.

 

[BMWCCA]

Well, most JBL fans just get their kits from Rick Cobb. I have for over ten-years. He knows what's correct for every model.
rcobb@tampabay.rr.com

 

[SaturationPt]

Actually, his 128H-1 kits are only 9/16ths. I was going to order from him but he doesn't have the wider roll, which is why I posted this (to help anyone else looking for the OE width roll). It is difficult to find.

Super great and helpful guy though, he's first in line for anything that he stocks when I order in the future.

 

[BMWCCA]

I just measured an original 128H-1 driver edge roll in a 4412A. 10/16ths. These are unmolested original drivers.
Also measured an original 127H-1 in an L80T, also 10/16ths.
(Actually both measured 40/64ths, but I was using a metal straight-edge and not a caliper.)

 

[SaturationPt]

Rick told me that I had to measure as there were several sizes of cones for those speakers, all four of my (original foam) measured larger than the 9/16 he had.

I will see whether the roll dia. changes once installed, I suspect that laying flat in the box it is wider than it is installed with the inner lip at the correct angle.

 

[BMWCCA]

Likewise, Rick had told me there were two cone sizes on the 128H. I didn't realize that carried through to the 128H-1. I suppose I'll find out eventually. Thanks for the info and research.

 

[SaturationPt]

I also noted a lot of chuffing through the port below ~50hz, trying to cure that one. 4312A does not have this problem, might just be the port material (thin polycarb tube vs laminated cardboard).

 

[Chris Brown]

I noticed that the roll is thinner than stock on most of the JBL foams that I have got from Rick Cobb, but I don't see any evidence that this is necessarily a problem. It certainly does not restrict cone travel, as it has not stopped my voice coil from hitting the pole piece from time to time when I push them too hard with bass-heavy content. The Rick Cobb foams for the 2214H woofers on my L100T speakers are the same in terms of the replacement having a thinner roll but it also does not seem to cause any problems. I do not notice any chuffing with my 4412 speakers, but then again 4412 and 4412a have different shape ports. I've also swapped the woofers between my L150 speakers (128H) and my 4412 speakers (128H-1) and did not notice any difference.

My 4412 before refoam:


After refoam:


You can see pretty clearly that the roll on the stock foam is wider. I did take cone measurements and send them with my request.

 

[BMWCCA]

Below is a before-and-after of an L80T with the original surround on the left and the Rick Cobb replacement on the right. I believe the original surrounds just get "flabby" before they disintegrate.

 

[SaturationPt]

I considered the "flabby before disintegrates" possibility also, mine aren't disintegrating yet but I was going to refresh several speakers and ordered these at the same time, not sure at what point it could become stretched or flabby but see different options, went with the ones closest to current.

The 4412 has an oval port, the replacement for the series (LSR32 / LSR6332) has a flared oval port, the 4312A has a heavy laminated cardboard port, ... this makes the 4312A & 4410A somewhat unique in their construction in the JBL Pro speakers (not completely unique) with a thin plastic slide-in port.

I am going to do some experimenting this weekend with the ports, and will be consulting a speaker designer / pro-dealer on port designs also to ensure that I'm not negatively affecting port tuning. Flared end, damping material on the port exterior surface, and even the soda-straw methods might help depending on what exactly is the cause.