Weird "out of phase" effect on JBL 2440

[retro soulman]

Today listening more carefully my 2440 (2441 diaphragms) 2390 combo i realise that the center image wasn't that solid. For many years i was a 2445 user (still loved them) and their center image (when the phase is correct) is solid and precise. Back on the 2440, i put a test record and the phase tests sound aaaalmost correct still without the rock solid imaging of my 2445. I open both drivers to look the terminals and wires are correct from the diaphragms (red spot etc) . Everything looks ok. Changing the phase on one of the drivers from my electronic crossover and the imaging goes to perfect and that is something very weird. The diaphragms are original and in good condition. What it could be?

[retro soulman]

Well it looks like its a false alarm. I swap the 2440 with the 2445 and almost the same out of phase effect happens. It looks like that the lenses help for this issue cause most of the time i have them removed. !!

[jbl4ever]

Hi what crossover frequency are you using and how big is the baffle behind the lens. Got a picture

[retro soulman]

Hi what crossover frequency are you using and how big is the baffle behind the lens. Got a picture

Im using a Bss fds 310. No not baffle !

[Robh3606]

You need a baffle board for those lenses to work properly at crossover.

http://www.lansingheritage.org/images/jbl/specs/pro-comp/horns-lens/page3.jpg


Rob:)