A Kicker subwoofer, like any manufacturer's low-frequency car audio speaker, is subject to the rigors of its environment. Temperature and humidity changes take a toll, as does the music played through the speaker. The quality of amplification can also create situations where the sound output requires you to test the components in your audio chain. A voltmeter, or more accurately a multimeter capable of measuring resistance, is useful for testing your Kicker subwoofer for proper performance.
Isolate the Subwoofer
Disconnect your subwoofer from the audio chain. There is no need to remove the speaker from its mounting if you can access the connecting wires, usually on or around the magnet at the base of the subwoofer. Remove both wires from the speaker's terminals, and be sure that the connectors do not touch the subwoofer's frame. This ensures that the subwoofer you are testing is not influenced by other components in the stereo system.
Determine the Subwoofer's Impedance
Locate the impedance rating of your Kicker subwoofer. It is usually printed on the speaker or stamped into the magnet. Kicker's website (listed below) may help you determine your speaker's rating if you cannot identify it on the subwoofer itself. Impedance is a crucial measure of how a subwoofer reacts to audio signals, and a deviation from its rating indicates a malfunction with the speaker. For most car audio applications, subwoofers are rated at two ohms or four ohms.
Prepare Your Multimeter
Set your meter to read resistance. While both resistance and impedance are measured in ohms, they are not electrically the same. Impedance is difficult to measure outside laboratory conditions, and resistance is sufficient to test your subwoofer. Resistance will be two-thirds to three-quarters of the impedance rating. Thus, for a 4-ohm unit, you will expect a value between 2.6 and 3 ohms, and between 1.3 and 1.5 ohms for a 2-ohm subwoofer.
Test Your Kicker Subwoofer
Attach each probe from your multimeter to a terminal on the Kicker subwoofer. Polarity doesn't matter; you will get the same reading with probes reversed. Note that some Kicker subwoofers have selectable impedance. Be sure your subwoofer is selected to the value you are measuring. The ohms reading for your subwoofer will be in the range outlined above if your speaker is working properly. Anything outside that range indicates that your subwoofer has a malfunction and needs replacement.
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