Online Tone Generator: Generate Sound Frequencies 1Hz–22kHz

What is an Audio Tone Generator?

In acoustics, sound engineering, electronic hardware testing, and music composition, the ability to generate mathematically pure audio frequencies is essential. A tone generator is an electronic instrument that outputs periodic electrical waveforms at specific frequencies, measured in Hertz (Hz), where 1 Hz represents one complete oscillation cycle per second.

Whether tuning an acoustic guitar to 440 Hz, testing subwoofer extension at 30 Hz, pinpointing room acoustic resonance flutter in a recording studio, or testing high-frequency hearing limits at 16,000 Hz, a clean signal source is required.

Our free online Tone Generator utilizes the HTML5 Web Audio API to synthesize continuous waveforms from 1 Hz to 22,000 Hz. With real-time waveform switching (Sine, Square, Sawtooth, Triangle), fine-grained numeric frequency control, quick acoustic presets, and an animated oscilloscope, you can calibrate any audio setup directly in your browser.

To detect incoming pitches or tune instruments via your microphone, check our companion Pitch Detector. To test your stereo channel balance, explore our Sound Test and Left Right Audio Test.

Understanding Periodic Waveforms and Fourier Harmonics

The shape of an audio waveform dictates its harmonic structure and sonic timbre. According to Fourier’s theorem, any complex periodic waveform can be deconstructed into a sum of simple sinusoidal waves:

    Sine Wave              Square Wave            Sawtooth Wave          Triangle Wave
       _                      _      _               /|     /|              /\    /\
      / \                    | |    | |             / |    / |             /  \  /  \
  ---/---\---            ----+ +----+ +----     ---/--+---/--+---      ---/----\----\---
         \_/                   |_|    |_|         /   |  /   |               \/    \/

1. Sine Wave (Pure Fundamental Tone)

The sine wave is the purest building block of sound. It contains only the fundamental frequency with zero harmonic distortion or overtone energy:

• Application: Acoustic room calibration, hearing tests, subwoofer bass sweeps, and distortion measurement.
• Sound Character: A clean, smooth, hollow whistle.

2. Square Wave (Odd Harmonics: 1/n Decay)

A square wave alternates instantaneously between maximum positive and negative amplitudes:

• Harmonic Composition: Contains only odd integer multiples of the fundamental frequency (3f, 5f, 7f, dots), with the amplitude of each harmonic decaying proportionally to 1/n.
• Application: Testing digital logic gates, synthesizer lead patches, and guitar fuzz effects.
• Sound Character: Piercing, buzzing, retro 8-bit chiptune sound.

3. Sawtooth Wave (All Harmonics: 1/n Decay)

A sawtooth wave ramps smoothly upward and snaps vertically downward:

• Harmonic Composition: Contains every harmonic overtone (both even and odd: 2f, 3f, 4f, 5f, dots) with 1/n amplitude decay.
• Application: Rich analog synthesizer brass and string emulation, speaker power testing.
• Sound Character: Bright, harsh, brassy, and buzzy.

4. Triangle Wave (Odd Harmonics: 1/n² Decay)

A triangle wave rises and falls in linear ramps:

• Harmonic Composition: Contains only odd harmonics like the square wave, but the overtones decay rapidly at 1/n^2 (e.g., the 3rd harmonic is frac{1}{9} amplitude, the 5th is frac{1}{25}).
• Application: Testing acoustic resonance without the harsh high-frequency buzz of square waves.
• Sound Character: Mellow, warm, flute-like tone.

The Human Hearing Spectrum Across Common Frequencies

Step-by-Step Guide to Audio Calibration

Follow these guidelines when using our tone generator for hardware diagnostics:

1. Start with Safe Volume: Always reduce your speaker or headphone volume to a low setting before pressing Play Tone. High-frequency tones above 10,000 Hz can easily clip small tweeters if played at 100% amplification.
2. Select Waveform: Choose Sine for standard acoustic calibration or Sawtooth when testing harmonic speaker distortion.
3. Calibrate Subwoofer Crossover: Set the frequency to 80 Hz (the standard THX subwoofer crossover point). Adjust your physical subwoofer phase knob (0^circ or 180^circ) to achieve the loudest, punchiest bass in your listening chair.
4. Identify Room Flutter Echo: Walk around your listening room while playing a 1,000 Hz sine tone. Notice how the sound becomes noticeably louder in room corners and quieter in the room center; this demonstrates acoustic standing waves.

The Physics of Acoustic Resonant Modes (Room Modes)

Every enclosed physical space possesses natural acoustic resonant frequencies known as room modes. When an audio frequency matches the dimensional distance between two parallel walls, standing waves form:

• Axial Modes: Sound reflects between two opposite surfaces (front-to-back, left-to-right, or floor-to-ceiling). These carry the highest acoustic energy.
• Tangential Modes: Sound reflects between four room surfaces.
• Oblique Modes: Sound reflects across all six room boundaries.

Using our tone generator to sweep through low frequencies (between 30 Hz and 150 Hz) allows acoustic engineers and home studio producers to locate exact resonant peaks where bass builds up boozily, helping guide the placement of bass traps and acoustic absorption panels.

In electronic repair workshops, audio technicians inject test sine waves into audio amplifier inputs while probing output stages with an oscilloscope. If the sine wave flattens, clips, or rings at high frequencies, failing capacitors or leaking transistors can be swiftly identified and replaced. This makes pure frequency testing a staple in every technician’s troubleshooting toolkit.

To test low-end subwoofer excursion in extreme detail, visit our Bass Test. To test your high-frequency auditory perception limits, take our Hearing Test.