Tone Generator

How to use the tone generator

1. Turn your speakers or headphones down to a low level before you start.
2. Type a frequency in Hz or drag the slider. The slider is logarithmic, so bass frequencies get as much room as treble. Use the -1 / +1 buttons for exact values.
3. Choose a wave shape. Sine is a pure tone with no harmonics; square, triangle and sawtooth add overtones and sound harsher.
4. Pick Left, Both or Right to send the tone to one speaker or earpiece.
5. Press Play. Change the frequency while it plays; the tone follows instantly. Press Sweep to glide from 20 Hz to 20 kHz.

What the results mean

The tone generator makes a steady wave at exactly the frequency you set. What you hear depends on your gear and your ears:

• Below 40 Hz: only subwoofers and good over-ear headphones reproduce this. Laptop speakers go silent or buzz; a buzz or rattle at low frequencies means something in the speaker or the desk is resonating.
• 100 Hz to 4 kHz: every speaker should play these clearly and at a steady level. A drop or wobble at a certain frequency points to a damaged driver or a room resonance.
• Above 12 kHz: adults gradually lose the top of their hearing range. If a tone at 15 kHz is silent for you but a younger person hears it, that is normal age-related change, not a speaker fault. Our hearing frequency test measures this step by step.
• Left / Right: the tone should come from the side you chose. Swapped sides mean the cable or balance setting is reversed. The sound test has more channel checks.

The waveform display shows the shape of the wave, not the sound coming out of your speaker.

Wave shapes and what they are for

A sine wave contains a single frequency and is the standard test signal: it reveals speaker resonances, hearing thresholds and room modes without any harmonics muddying the result. A square wave contains every odd harmonic and sounds hollow and buzzy, which is useful for hearing how a speaker handles sharp edges, and for synth and chiptune sounds. A triangle wave has the same odd harmonics but much weaker, so it sounds like a softer sine. A sawtooth wave contains every harmonic and sounds bright and brassy, which is how most synthesizer leads start.

Musicians use the tone generator for tuning: 440 Hz is A4, the standard concert pitch; the note name under the slider updates for any frequency. Audio engineers use 1 kHz as a reference level, 60 Hz to find mains hum, and sweeps to find rattles and resonances in cabinets and rooms. Pest-deterrent and dog-whistle uses above 17 kHz depend on speakers that most laptops and phones cannot reproduce well, so do not rely on them.

Frequency ranges to try

20-60 Hz: sub-bass; feel it more than hear it. 60-250 Hz: bass; kick drums and bass guitar. 250 Hz-2 kHz: midrange; most of the voice. 2-6 kHz: presence; speech clarity and sibilance. 6-20 kHz: brilliance; cymbals and air. A speaker that sounds even across a slow sweep is well balanced; one that jumps in loudness at certain spots is coloring the sound.

Common problems and fixes

I hear nothing

Check the volume slider here and the system volume, and that the right output device is selected. Browsers only start audio after a click, so press Play again if you changed tabs. Frequencies above 16 kHz may be inaudible to you even though the speaker is producing them.

The tone crackles or distorts

Lower the volume here. Square and sawtooth waves peak much higher than a sine at the same slider position. Bluetooth speakers often distort below 60 Hz.

The tone is on the wrong side

Swap the left/right cable or check the balance setting in your sound settings. On headphones, make sure the L and R cups are on the right ears.

The sweep seems to drop out in the middle

A dip at one frequency is a resonance or cancellation in the speaker or the room. Move the speaker or your head a little and sweep again; if the dip moves, it is the room, not the speaker.