I bought a used pair of JBL 4311B's in apparent good condition. After extended listening it became apparent one cabinet's tweeter was not as loud as the other. I maxed the treble control on both speakers so the setting is identical, that is not the issue. I read some posts recommending cleaning the pots, I did that as best I could, it was quite a chore to get the crossovers out and I sprayed thoroughly into the back of the L-pads in the bent openings, turning the knobs. I had to remove the tweeter to get at the crossover, so while I was at it I tested it with a multimeter. The readings I got were 4.1-4.2 ohms, tweeter labeled LE25-2. I read that 3.5-3.8 is spec. Maybe this is the real issue? could the frail wire beneath the foam surrounds be the issue? I noticed that part of it was already part way pulled back, not firmly glued down. Maybe this was due to a tweeter recone?
I've been listening to the speakers a bit now and I can't tell if there is improvement, still seems weak on the one tweeter. I've also tried swapping amp channels and cables to eliminate that possibility.
Even if I sort this problem out, I feel left somewhat wanting with the high end response rolling off at 15k. Maybe I should look at getting 4312's with the titanium tweeter rather than trying to tweak these?
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Originally Posted by 4313B
