Here's an old show description just popped up that I found interesting.
RE/P Files: Clair Brothers At the L.A. Sports Arena With Bruce Springsteen, Circa 1980 - ProSoundWeb

There's a specific passage about using the JBL 2441 with a Tad driver.
"A Clair Brothers employee in the speaker department noted a strange resonance when testing the new JBL 2441 drivers and discovered that a drop of nail polish placed on the back of the diaphragm damped out the resonance. (JBL has since included such a procedure in its production process.)"