Tools
Speaker test
Check every channel, the wiring and the bass, with tones that start quietly.
How the test works
Channel test
We play a short sound through one channel at a time. Tick the ones you hear. Surround channels appear when your output reports more than two.
Polarity test
The same tone plays in phase, then with one side inverted. On correctly wired speakers, the in-phase version sounds fuller and centred; if the inverted one sounds fuller, one speaker is wired backwards.
Sweep and tones
A slow sweep from deep bass to high treble reveals rattles, buzzes and dropouts. Single tones let you check a frequency on its own.
Safe volume
Every tone starts at a low level. Set your system volume low first, then raise it slowly.
What your results mean
A channel is missing
Check the cable and connector on that side, the balance setting in your system's sound settings, and whether a mono-audio accessibility option is on.
Bass is weak or absent
Small laptop speakers can't reproduce deep bass; that's physics, not a fault. On a sub, check its power, crossover and volume knobs.
Rattles during the sweep
A loose object, grille or driver. Note the frequency where it happens and check what vibrates.
Questions
How do I test left and right speakers?
Press Left, then Right. You should hear each sound only from that side. If both play from both sides, a mono-audio setting may be on.
Why can't I choose my output device?
Only some browsers let a page pick the output. Others always play through your system default, which you can change in your sound settings.
Is the high-frequency test safe?
Tones start quietly. Keep your volume low, especially with headphones, and stop if anything is uncomfortable.