How different are they? (JBL 8`s)

[FE3T]

I have good pair of JBL 2118H`s here
And are avaiting a pair of 2118J who needs reconing.

When searching for info, looking at pics and recone parts i have noticed quite a few similarities with other JBL 8`s

2119 looks to have just a different moving assembly in the same basket as the 2118.

108H`s supposely just a different moving assembly in the same basket as the 2118. (aquaplased 2118 or 2119 parts?)

116H-1 ,2 and 3, the aluminium frame looks identical, probably a smaller magnet than the 2118

117H the aluminium frame looks identical, definitively a smaller magnet, (smaller voicecoil?) than the 2118

All this makes me wonder:
Can it be possible to use a aftermarket 116H-2 recone kit (separate parts) and install them in a 2218 basket and end up with a driver slightly more capable in the bass area than the 2118, 2119 and the 108H, while still getting a bit higher sensitivity than a stock 116H-2?

When looking at recone parts for the 2118 and the 116H-2 i find the following:

Both have the same size dustcap
Both use a 1.250" long voicecoil former
Both have a 2" voicecoil
Both have .289" heigth cup spider with 4.635" diameter

Differenses:
116H-2 have .625" windings
2118H have .500" windings
116H-2 have a 1.545" deep cone
2118H habe a 1.525" deep cone

Unknown:
Winding thickness on the respective coils (anyone know?)

any opinions from the reconers on the site?

Is it even worth a try, or are a 108H kit a better option if im not happy with the stock 2118`s low extension?

 

[GordonW]

That should work. I'd expect less bass extension than the 116H-2, but higher efficiency, due to greater magnetic flux. Would work in a smaller box well, but with less low bass.

You'd need to measure it (using something such a a Woofer Tester)... but I think you're on a good logical track.

Of course, you'd have to test-fit (with a shim) the 116H-2 voice coil in the 2118 magnet gap. As long as you have adequate clearance inside and outside the windings (at least the thickness of the shim used in the 116H-2, between the inside of the coil and the pole piece, and the outside of the coil and the top plate), you should be just fine transplanting the parts.

Regards,
Gordon.

 

[GordonW]

BTW: I sort of created a "108 equivalent", using a 116 cone, the 2118 spider, surround, dustcap and voice coil, and a 2118 frame/magnet. The higher mass of the 116 cone made the parameters much closer to a 108, than the stock 2118. I'm thinking of making some 250Ti clones, with those, a pair of reconed LE14s, and some 104H-2s... still looking for the other parts.

Regards,
Gordon.

 

[FE3T]

That should work. I'd expect less bass extension than the 116H-2, but higher efficiency, due to greater magnetic flux. Would work in a smaller box well, but with less low bass.

You'd need to measure it (using something such a a Woofer Tester)... but I think you're on a good logical track.

Regards,
Gordon.

Thats just what i hope for, the goal are to create a potent driver for HT service,together with some "2236" drivers if i manage to find a source for the voicecoil (struggling a bit here, so any hints would be helpful)