Speaker Polarity Test – Check If Speakers Are Wired Correctly

Every speaker terminal is marked + and –. When both speakers are connected the same way, their cones move outward together and the sound from each reinforces the other in the middle of the room. Swap the wires on one speaker and that cone moves inward while the other moves outward. The two outputs partly cancel, so bass gets thin and the centre image becomes vague and “phasey”, as if it came from inside your head or from everywhere at once.

Polarity and phase are often used as synonyms. Strictly, polarity is a simple sign flip of the signal, while phase is a time-dependent shift that varies with frequency. A wiring mistake is a polarity problem; our phase test covers the broader topic.

With correct wiring, the normal buttons give a solid, centred sound and more bass. The reversed buttons deliberately invert the right channel, so on a correct system they should sound hollow and wide. If it is the other way round, the normal version sounds hollow and the reversed version sounds right, then one speaker is wired with + and – swapped.

Bass tones make the difference most obvious because long wavelengths cancel strongly. If you can hardly tell the versions apart, move closer to the exact centre, turn off any “3D”, “virtual surround” or room-correction processing, and try the 80 Hz pair again.

1. Turn the amplifier off.
2. Follow the cable from one speaker back to the amplifier. One conductor is usually marked with a stripe, ridge, text or copper colour.
3. Make sure the marked conductor goes to + (red) at both the amplifier and the speaker, for every speaker.
4. Power on and repeat the test.

On powered speakers and computer speakers the cable is usually keyed so it cannot be reversed. There a hollow result usually means processing in the sound driver or a fault in one speaker; check with the speaker test and the stereo test.

Related guides and fixes

Learn more in these guides: No sound on Windows, No sound on Mac, Headphones only one side, Speakers crackling, How to test speakers, How to test headphones.

Headphones cannot suffer from room cancellation the same way, but a reversed driver still makes the centre image feel wide and strange. The reversed buttons let you hear what that sounds like. If the normal version sounds like that on your headphones, try the headphone test and check whether a spatial audio mode is enabled.

Many subwoofers have a 0°/180° switch. Play the bass test 80 Hz tone near the crossover at your seat and flip the switch: keep the position that gives more bass. See also our guide to testing a subwoofer.

This is a listening comparison, not a measurement. It cannot tell you which individual driver inside a multi-way speaker is reversed, and some speakers intentionally wire a tweeter in reverse polarity as part of the crossover design. Use it to catch the common mistake: an entire speaker connected backwards.