Originally Posted by
kelossus
Thank you very much for the responses guys. I attacked it this morning after with a fresh mind and had a slight improvement.
I cleaned the gap again, shuffled the shims and I found only one quadrant needs to be shimmed. Once shimmed I installed 3 of the mounting screws and ran a 500hz-1200hz sweep. Edgewound on an earlier thread specified 3.5v for the 16ohm phragms but I didn't take it over 2.5v, 3.5v would have been insanely loud. Couldn't hear any fouling so I assembled it all back together. I am now an expert at removing/installing the 2440 driver from the 4350 cabinet by myself though I hope to never do it again.
These sweeps aren't as good as my initial ones but the 6% THD from yesterdays sweep is now gone. If I can get another brand new 2441 Diaphragm I will send these interstate to an expert and get them fitted and recharged. Sadly in Australia there a few who can service these JBL drivers and even fewer that would back their installation up with measurements.
BLUE TRACE = LEFT 2441, the one I had had issues with. RED TRACE = RIGHT 2441
WITH 2308 ATTACHED, 1 foot away from speaker
WITHOUT 2308, 1 foot away from speaker