1987 - 2017: Thirtieth Anniversary!
Best viewed in "landscape" mode.
Determine Speaker Polarity
Speaker polarity is defined quite simply: when a positive voltage is applied to the positive terminal of a speaker (relative to the negative terminal), the diaphragm (cone, dome, ribbon, etc.) moves outward into the listening space.
Conversely, when a reversed voltage is applied, the cone moves backwards, or inwards, away from the listener.
The easiest way to check polarity is with a small DC voltage - a 1.5 volt cell, for instance. This will be safe for virtually any dynamic (coil and magnet) driver made, although motion of tweeter domes can be very difficult to observe visually. With them it is often easier to very lightly touch them while applying the voltage (be very careful when touching metal domes).
Entire systems can be more complex, as some drivers are often wired relatively "out of phase" in order to maintain phase linearity at the region where they cross over to other drivers. Thsi is seen a lot with midranges in three-way systems using second-order filters. What matters, though, in defining the polarity of the system is which way the woofer is wired, and the woofer crossover will usually pass DC current, making thsi test fairly easy.
Older JBL drivers used the opposite convention. Since many of these public-address system speakers are stil in use, and in some cases, JBL still makes new replacements, it is very important to know what one is dealing with when combining these systems with other speakers. JBL has thoughtfully posted a precise listing of these parts on their website, and I have saved a copy of it here.
7 Kelsey Road, Lee, New Hampshire 03861