Frequency Generator – Online Tone Generator

• Test speaker and headphone range: find where bass fades and treble disappears.
• Find rattles: slowly sweep the bass to see which frequency makes a cabinet, desk or car panel buzz.
• Explore your hearing range: most adults hear up to 14–17 kHz (not a medical test).
• Tune instruments: A4 = 440 Hz is concert pitch.
• Teach physics: demonstrate beats, standing waves and resonance.
• Describe tinnitus pitch to a professional.

A logarithmic sweep gives every octave equal time, matching how we hear. A linear sweep rushes the bass and lingers in the treble. Listen for sudden drops (room nulls or crossover issues), peaks (resonances), buzzes (loose parts) and where sound disappears (the limit of your equipment or hearing).

Sine: one pure frequency, best for measurement. Square: odd harmonics at 1/n, hollow and buzzy. Triangle: odd harmonics at 1/n², soft. Sawtooth: all harmonics at 1/n, bright. A 1 kHz square wave also contains 3, 5, 7 kHz and more.

½-step buttons move one semitone (×1.0595); octave buttons double or halve the frequency.

Keep long tones quiet, especially above 10 kHz and below 40 Hz. Output is limited by your device's sample rate (44.1/48 kHz → max ≈22 kHz), and many speakers can't reproduce the extremes.

Pure versus harmonic tones

A sine has one frequency; square, triangle and sawtooth add harmonics that make the tone brighter.

Square wave

Odd harmonics give a hollow, reedy sound.

Triangle wave

Weak odd harmonics give a soft flute-like tone.

Sawtooth wave

All harmonics give a bright, buzzy tone.

Concert pitch: A440 vs A432

Modern pitch is A = 440 Hz; claims that 432 Hz is healthier have no evidence.

Tinnitus matching and masking

Use the tinnitus matcher to find the pitch and noise for masking.

Identifying room modes

Slowly move the frequency between 30 and 200 Hz; tones that boom are room modes.

Frequency reference chart

Sub-bass 20–60 Hz, bass 60–250 Hz, low mids 250–500 Hz, mids 500–2 kHz, presence 2–6 kHz, brilliance 6–20 kHz.

Low and very high frequency warning

Avoid long, loud tones below 20 Hz or above 15 kHz; they can harm speakers and ears without seeming loud.

Start generating a tone

Pick a frequency, waveform and volume, then press Play.

Science experiments with tones

Show resonance with a glass, make sand patterns on a speaker (Chladni), or demonstrate beats with two close tones.

Choose the right signal for your question

Sine for pitch and limits, square for harmonics, noise for balance, sweep for resonances.

Very low frequencies can be hard to hear but still loud enough to stress speakers, and high-frequency tones at high level are uncomfortable and can harm hearing. Start at low volume, keep sessions short, and never push volume to make an inaudible tone audible.

Notes use twelve-tone equal temperament with A4 = 440 Hz; each semitone multiplies frequency by about 1.0595. Middle C (C4) is 261.63 Hz. Use the note selector to play a reference for tuning or singing, or the pitch detector to measure what you play.

Play the same tone at fixed volume and step through 20, 40, 60, 80 and 100 Hz, then up through the octaves. Tones that suddenly drop out or boom show the limits of your speakers and room. The frequency sweep does the same continuously.

This online frequency generator works on Windows laptops, MacBooks, Android phones and iPhones without any app. Type a frequency in Hz or use the slider, choose a waveform and press play. On phones, keep the screen on while a tone plays, because some phones pause web audio when the screen locks. Laptop and phone speakers usually cannot play below about 100–200 Hz, so use earphones or external speakers for low tones.

Learn more in these guides: No sound on Windows, No sound on Mac, Headphones only one side, Speakers crackling, How to test speakers, How to test headphones.