You need to determine which speaker wire is positive before connecting the wires to an amp. Speaker cable is sometimes mismarked with striping that is supposed to identify the positive wire. If speaker polarity is incorrect, it can cause imbalance in multichannel speaker systems and even eliminate certain signal tones altogether. You can test the speaker wires for correct polarity to ensure your system delivers the bast sound possible.
Remove the front cover from the speaker cabinet. Pull the mesh cover and its frame off the front of the cabinet so that you can see the speakers. Use a flashlight to view the woofer through the cover if it doesn't come off.
Disconnect the speaker cable from the amp or receiver.
Briefly touch the bare ends of the speaker wires to the terminals on a 1.5 volt AA battery. Hold the wire marked with a stripe on the positive cap and the other wire on the negative flat end.
Watch the reaction of the woofer when the wires touch the battery. If the woofer pushed forward, then the polarity is proper. In that case, the wire touching the positive battery cap is the positive wire. If the woofer recoils back, then the polarity is in reverse; the positive wire is touching the negative battery terminal. Mark the positive wire for accurate connection to the amp.
Reconnect the speaker wires.
Things You'll Need
AA 1.5 volt battery
Do not use the battery test on speakers that are connected to a system.
Do not use a battery with more than 1.5 volts for testing home stereo speakers.
Do not hold the speaker wires against the battery for more than a few seconds. The battery can blow the speaker if it's connected for too long.