Speaker test — check left, right & stereo

How to use the speaker test

1. Turn your volume up to a comfortable level and make sure nothing is muted. Start low — a 440 Hz tone can be sharp when loud.
2. Tap Left to send the tone only to your left speaker, Right for the right, or Both to play it centred through both at once.
3. Watch the live oscilloscope — the waveform shows on the lane of whichever speaker is getting signal, so you can confirm output even in a noisy room.
4. Drag the centre meter up or down to set the test volume.

What you should hear

• Left: the tone from your left speaker only, with the right silent.
• Right: the tone from your right speaker only, with the left silent.
• Both: an even tone from the centre, equally loud on each side.

If the tone is missing on one side, noticeably quieter on one side, or comes from the opposite speaker to the button you pressed, you have a channel, balance, or wiring problem — see below.

Is my speaker working?

If you hear the 440 Hz tone clearly on Both, your speakers and your computer's audio output are working. From there, any remaining silence is downstream — a specific app's output device, a muted browser tab, or a cable — not the speakers themselves.

Only one side plays?

A dead or weak channel is almost always hardware or balance, not software:

• Balance slider — the most common cause. On Windows, open the classic Sound control panel → Playback → your device → Properties → Levels → Balance, and set left and right equal. On macOS, go to System Settings → Sound → Output and centre the Balance slider.
• Cable or jack — a worn 3.5 mm headphone jack or a damaged cable often kills one channel. Try another cable or port, and push the plug fully in.
• Swapped sides — if Left plays on the right, your speaker wires or connections are reversed; swap them at the speaker end.

No sound at all?

Work through these in order:

1. Raise the system volume and confirm the output is not muted — including any per-app or browser-tab mute.
2. Check you are sending audio to the right device. Headphones, a monitor over HDMI/DisplayPort, a USB sound device, and built-in speakers are separate outputs — pick the one you are actually listening to in your OS sound settings.
3. USB or Bluetooth speakers: reconnect them. For Bluetooth, make sure the device is connected as an audio output, not only paired.
4. HDMI or DisplayPort monitor: audio may be routing to a screen with no speakers. Switch the output back to your speakers or headphones.
5. Restart the browser, then run the test again.

The test works but an app is silent?

If you hear the tone here but a call, game, or video has no sound, your speakers are fine — that app is sending audio to a different output device or is muted. Check the app's own audio settings, not your hardware.

How this test works

The test uses your browser's Web Audio API to generate a clean 440 Hz sine wave (the musical note A) and pans it fully left, fully right, or to the centre with a stereo panner, so each physical speaker can be checked on its own. Everything runs locally in your browser — no audio is recorded, uploaded, or stored.

Frequency sweep: find rattles and your speaker's range

Open Advanced tests to run a frequency sweep — a tone that rises smoothly from a deep 20 Hz rumble up to a high 20 kHz whistle. It does two useful things. First, it surfaces rattles: if one particular pitch makes something vibrate — a loose speaker grille, a panel, an object on your desk, or a damaged driver — you hear a distinct buzz at that frequency. Second, it shows your speaker's real limits: small laptop and phone speakers produce nothing below roughly 150–200 Hz, so silence at the very bottom of the sweep is normal for them, not a fault. A healthy speaker plays the whole sweep smoothly, without dropouts or distortion. The Bass only preset repeats the low end on its own — the quickest way to check whether a subwoofer is actually working and how low it reaches.

Speaker polarity (phase) test: are your wires reversed?

Each passive speaker has a + and a − terminal. If one speaker in a stereo or car pair is wired the wrong way round, the two speakers move in opposite directions and partly cancel each other — the result is thin, weak bass and a vague centre, with no clear point the sound comes from. The polarity test plays the same sound through both speakers two ways: in phase (correct) and out of phase (one inverted). In phase should lock to a solid spot in the centre; out of phase sounds hollow, wide, and everywhere at once. If the out-of-phase version sounds like your normal setup, swap the two wires on one speaker and your bass and centre image will come back. This applies only to speakers you wire yourself — built-in, USB, and Bluetooth speakers cannot be connected backwards.