Left Right Speaker Test
Play the left channel, then the right, then both: the sound should come only from that side. The tone generator covers 20 Hz to 20 kHz, and pink noise has equal energy in every octave.
How to use
- Keep the volume low, then press Left. The sound should come only from the left speaker or earbud. Press Right, then Both. Press the same button again to stop.
- Choose Tone or Pink noise as the sound. Pink noise is easier to place by ear on small speakers.
- For the tone generator, type a frequency from 20 to 20000 Hz, drag the slider, or tap a preset such as 100 Hz, 440 Hz or 1 kHz. Press Play and change the pitch while it sounds.
- For the phase test, play In phase and Out of phase one after the other and compare how they sound. See the notes below the buttons.
How it works
The tone is a pure sine wave made by a Web Audio oscillator. The frequency slider is logarithmic: every step multiplies the frequency by the same factor, so 20 Hz to 20 kHz (three decades) fits one slider and low pitches are easy to set precisely.
Pink noise has equal energy in every octave, which is why it sounds like steady rain rather than a hiss. It is generated in your browser and looped. Left, Right and Both use the browser's stereo panner. Where that is missing, the tool sends the sound to separate left and right gains through a channel merger instead.
The phase test sends the same signal to both channels, once as it is and once with the right channel multiplied by -1 (polarity flipped). Sound that is the same in both channels adds up in the air between two speakers; with one flipped, low frequencies partly cancel.
The volume slider follows a squared curve and tops out well below full scale, so small movements near the bottom make small changes. Every start and stop fades over a fraction of a second to avoid clicks.
FAQ
How do I know left and right are the right way round?
Press Left. Only the left speaker or the earbud marked L should play. If it comes from the other side, check the cable or the way you wear the earphones, then the balance setting in your device's sound or accessibility options.
I hear nothing, or only one side.
Raise the media volume and check that the right output device is selected. On iPhone, switch off the silent (ringer) switch on the side. Also check Bluetooth connection, mono audio in accessibility settings, and that nothing else is muting the page.
Is this a hearing test?
No. It is a quick check of your speakers or earphones, not a hearing test or a medical assessment. Many devices cannot reproduce 20 Hz or 20 kHz at all, so a missing sound at the extremes usually says something about the device. If you are worried about your hearing, ask a professional.
What does the phase test show?
It helps you spot a speaker wired with reversed polarity. In phase, the noise sounds full and centred between the speakers. Out of phase, it sounds thinner with weak bass and no clear position. If the In phase button sounds like the thin one, one speaker is probably connected backwards.
Is it safe to play loud tones?
The volume starts low on purpose. Raise it slowly, because very low and very high tones can be tiring or unpleasant at volumes that sound moderate. Stop if anything feels uncomfortable, and do not use headphones at high volume.