le15b recone kit from sound speaker repair
For anyone interested, received two kits this week, first thing I noticed is the external cloth surround is glued on the front of the cone, took a couple of measurements on the dimension of voice coil and look similar. Once I will be back home next week I will compare to the original NOS C8RLE15B I have and give more details. Anyone have experience with sound speaker repair kits?
Giuliano
Greater moving mass could be the culprit
Quote:
Originally Posted by
1audiohack
Probably not an issue in a domestic setting but most of the failures I see with non JBL kits are 10-15 rounds of the bottom of the voice coil loose and in the bottom of the motor.
Also that real high Z at resonance as compared to all the other drivers is odd. It would be intersting to observe the "geezer" test speaker with a strobe light. I can usually tell of a coil or spider or some part of the suspension is disconnected or a diaphragm is broken via a high impeadance peak. Something isn't peachy.
Barry.
It seems to me that a higher mms figure, such as what a copper coil substituted for the aluminum coil would undoubtedly contribute, would result in a higher mechanical resonance... which in turn would create greater back-emf that translates to a higher Zmax at resonance. It would also explain a lower output across the frequency range, as more energy would be lost pushing that heavier moving mass...
2245H cone assy weight/mms spec
Quote:
Originally Posted by
dprice
I used one of the 2245 kits from mackenzie for the sub I built for my brother about two years ago. It did not have the aquaplas on the cone and did not appear to weigh enough to meet the JBL moving-mass spec for the 2245. I expected this from what I had read in this thread so I simply painted duratex (hillbilly aquaplas?) on to the rear of the cone and kept weighing it until I got it in the ball park. Cosmetically it is a dead ringer for my JBL 2245 in the B460. I was using a blown 2240 driver so I didn't have an old 2245 cone to use as a reference for the weight. Obviously a real JBL kit is (was?) the way to go but it wasn't in the budget for this build. Two years later the low-budget recone is working fine.
Don
Don, your post prompted me to pull out my salvaged 2245 cone assemblies to weigh them. All three have the rotted foam removed, but the dust cap, tinsel leads, and spiders are intact but stretched out.
The weights are 159g, 160g, and 160g
JBL T/S parameters specify 185g Mms
Considering mine are missing the foam surround, 25g seems appropriate to make up the difference between my weights and JBL T/S specs.
Has anybody here bought re-foam kits that can weigh the foam surround?
One of these days I'll surgically remove the sunken spider on one of these and re-spider, re-foam, and re-install it in the frame.
One of these days... :hmm: At least that's what I keep telling myself :p