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Topic: JBL Horns
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Steve Guttag
We forgot the crackers Gromit!!!
![](http://www.film-tech.com/ubbmembers/268e.gif)
Posts: 12814
From: Annapolis, MD
Registered: Dec 1999
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posted 05-22-2010 09:51 PM
Positive voltage on red or "+" terminal having a cone driver move out of the magnet is the convention of most.
JBL did it in reverse in a "retaliation" to Altec convention since James B Lansing was the father of both.
As for what drivers are in "normal" phase versus reverse...if a JBL driver is a legacy driver (can be a direct replacement of an earlier driver) then it will follow the traditional JBL convention of reverse phase. If it is a NEW JBL driver that does NOT DIRECTLY REPLACE a legacy driver, then it will follow normal phase.
Thus 2225, 2226 drivers will follow reverse phase. 2425, 2426, 2445, 2446, 2450 drivers will also follow reverse phase.
Subwoofers is where it gets tricky. The 4645 (original) used the 2245H, it is reverse phase. The 4645B and 4645C use the 2242...this is NOT a direct replacement of an earlier driver so it follows NORMAL phase. The 4642A subwoofer uses 2241 drivers...the 2241 IS a replacement of the 2240 driver so it follows REVERSE phase! JBL states that the 4141 and the 4642A follow NORMAL phase...which means the cabinets have to be wired reverse internally. I can and have found them wired wrong and, in the case of the 2242A, with each driver wired opposite (to the terminals on the cabinet)!
As Gord says...use a phase checker to ensure you are wired in-phase. The CP650 and CP750 even give you the "thump" for the phase checker to work from.
Steve
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