Check left/right channels and frequency response to make sure your speakers or earbuds are working.
β οΈ Lower your device volume before starting. Sudden loud tones or high frequencies can be unpleasant or harmful to your hearing, especially with earbuds.
Press play to hear the test tone.
New earbuds, a headset, or laptop/monitor speakers can sometimes have swapped left/right channels or a dead side straight out of the box. This tool generates clean test tones in the browser to play the left, right, and both channels separately, and sweeps the full 20Hz-20kHz range so you can check the audible frequency range.
Pressing "Left," "Right," or "Both" plays a 440Hz reference tone on just that channel. With earbuds in, press each button and confirm the sound actually comes from the matching ear. If pressing "Left" plays sound on your right side, the channels are swapped, or your earbuds' L/R marking is on the wrong ear.
Moving the slider from 20Hz (lowest bass) to 20,000Hz (highest treble) plays a pure tone at that frequency in real time. Human hearing varies a lot between people, and it's completely normal for high frequencies (typically above 15kHz) to become harder to hear with age. If a speaker crackles or cuts out at low frequencies, that can indicate a damaged driver.
If only one side plays sound, check: (1) the earbud jack is fully inserted, (2) your OS sound settings' output balance is centered, (3) a Bluetooth earbud isn't connected in mono call mode. If sound only distorts at specific frequencies, lower the volume and retest β if it persists, it may point to a hardware issue.
During a frequency sweep, high tones (above 15kHz) or high volume can sound much sharper and louder than expected. Always start at a low volume and increase it gradually. Be especially mindful if children or pets are nearby β very high frequencies that feel mild to adult ears can still be uncomfortable for them.