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Speaker / Stereo L-R Test

Check each speaker, confirm the channels are the right way round, and find a rattle.

Volume warning

This test plays tones that can be loud and may damage hearing or speakers. Turn your volume down before starting, then raise it gradually.

How this test works

Three short tones. The first goes to the left channel only and the second to the right, each routed through a channel merger so the silent side is genuinely silent rather than merely quiet — a panner leaves a trace of signal in the opposite channel, which is exactly what this test is trying to detect. You say which side you heard each from, and the tool works out whether both outputs are alive, whether they are the right way round, and whether they are separated at all. The third tone is 100 Hz on both channels, the frequency at which a loose driver or something resting against the cabinet buzzes while everything sounds fine at speech frequencies.

What the results mean

Channels isolated
The left tone came from the left and the right from the right. Both outputs work and the wiring is correct.
Channels crossed
Both speakers work but the sides are reversed. That is a cable or configuration problem, not a broken speaker — usually swapped leads at the amplifier.
Not separated
One channel was audible from both sides. Normal on a phone, a laptop or a soundbar. On a separated stereo pair it points at a mono cable or a mono output setting.
Buzz at 100 Hz
A mechanical fault rather than an electrical one: something is vibrating against the cone or the cabinet. It is worst on bass and can be inaudible on speech, which is why it needs its own tone.

Common problems and fixes

One side is much quieter than the other
Check the balance slider in your OS sound settings first — it is the single most common cause and costs nothing to rule out. Then reseat the cable at both ends and try a different one.
I hear both tones from both speakers
On a laptop, phone or soundbar that is expected. On separate speakers, check whether the output is set to mono and whether the cable is a mono jack in a stereo socket.
There is a buzz on bass but speech is fine
Something is loose or resting against the cabinet. Clear the top of the speaker, check the mounting screws, and press gently around the driver surround while the tone plays — if the buzz changes, you have found it.
No sound at all from either side
Rule out the obvious in order: volume, mute, and the output device selected in your OS. A pair of headphones tells you immediately whether the fault is before or after the sound card.

Frequently asked questions

How do I test if my speakers work?

Play the left tone and the right tone above and say which side each came from. Both audible from the correct side means both outputs are driving sound and the channels are wired correctly. Silence on one side, with the other playing at the same level, is a dead output — a failed driver, a broken cable or a bad connection at that speaker.

How do I know if my left and right speakers are swapped?

Play each tone and answer honestly about which side it came from. If the left tone comes from the right speaker and the right tone from the left, the channels are crossed. That is a wiring or configuration fault: check the cables at the amplifier and any balance or channel-swap setting in your sound software. Nothing is broken.

Why do my speakers buzz on bass?

Almost always mechanical. A driver that has loosened in its mounting, a cabinet panel that has come unglued, or something resting on top of the speaker vibrating in sympathy. It appears at low frequencies because that is where the cone moves furthest. Distortion that appears only at high volume across all frequencies is different — that is the amplifier reaching its limit.

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