Tone Generator

About Tone Generator

This online tone generator creates audio test tones and signals with various waveforms. Generate pure sine waves for audio testing, square waves for synthesis, sawtooth waves for subtractive synthesis, and pink or white noise for acoustic measurements. All tones are generated in your browser and can be downloaded as high-quality WAV files.

What is a tone generator used for?

A tone generator produces a pure, controlled audio signal — sine wave, square wave, triangle, sawtooth, white or pink noise — at a frequency, level, and duration you specify. Audio engineers use it to test loudspeakers and headphones for buzzes and resonances, calibrate sound system gain structure, verify hearing-loss boundaries, train ear identification of pitch, generate timing references, and create base material for synthesis. ENT clinicians use pure tones at 250, 500, 1000, 2000, 4000, and 8000 Hz for audiogram testing. Producers use them as side-chain triggers, kick drum substitutes, or sub-bass reinforcement. Unlike recorded audio, generator output is mathematically defined, so the result is repeatable and free of room noise — ideal for precision measurement and benchmarking equipment.

What is the difference between a sine, square, triangle, and sawtooth wave?

A sine wave is the simplest periodic signal: a single fundamental frequency with no harmonics — sonically pure and flute-like, used for testing because any distortion shows up as extra harmonics on a spectrum analyser. A square wave contains the fundamental plus all odd harmonics (3rd, 5th, 7th, ...) at decreasing amplitude, sounding hollow and reedy like a clarinet; useful for digital timing and bass synthesis. A triangle wave also has only odd harmonics but they decay faster (1/n²), giving it a softer, sweeter tone close to a sine. A sawtooth wave contains every harmonic (odd and even), creating a bright, brass-like timbre rich enough for filtering into almost any synth sound. Each waveform has the same fundamental frequency but vastly different timbres because of harmonic content.

What is the audible frequency range and why does it shrink with age?

Young, healthy human hearing covers approximately 20 Hz to 20,000 Hz, but the upper limit drops about 1-2 kHz per decade of life, a phenomenon called presbycusis. By age 30 most adults cannot hear above 17 kHz; by 50, often not above 14 kHz; by 70, often not above 8-10 kHz. The loss is permanent and starts with the high-frequency hair cells in the cochlea, which receive the most mechanical work and damage first. Use the tone generator with caution at high frequencies — what you cannot hear can still be present at dangerous levels. Below 20 Hz signals are felt as vibration rather than pitch (infrasound); above 20 kHz is ultrasound, audible only to bats, dolphins, and some young children.

How do I use tones to test my speakers or headphones?

Run a frequency sweep from 20 Hz to 20 kHz at a moderate level (about -20 dBFS) and listen for buzzes, rattles, missing ranges, or sudden level dips. Buzzes typically reveal a loose driver, panel resonance, or amplifier issue at a specific frequency. A dip in the 200-400 Hz range is often a room mode caused by your listening position. Test left/right balance with separate stereo tones to confirm channel routing and check for crossed wires. For subwoofers, sweep 20-120 Hz; for tweeters, 4-20 kHz. Use a fixed sine at 1 kHz to verify gain matching across channels with an SPL meter. Always start at low volume; a 0 dBFS tone can damage tweeters and your hearing instantly at high amplifier settings.

What is white noise vs pink noise vs brown noise?

White noise contains equal energy per Hz across the spectrum — every frequency has the same power, which makes it sound bright and hissy because the ear perceives logarithmically and the upper octaves contain proportionally more total energy. Pink noise has equal energy per octave: each octave from 20-40 Hz, 40-80, 80-160, etc. contains the same total power, mimicking the natural distribution of music, rainfall, and ocean waves. Pink noise sounds balanced and pleasant, and is the standard test signal for loudspeaker tuning, room acoustic measurement, and audio-system frequency response analysis. Brown (Brownian/red) noise drops 6 dB per octave above pink, sounding even darker and more rumble-like — often used for relaxation, masking tinnitus, or testing low-frequency response.

Why do I hear strange beating or warbling when I play two close frequencies?

When two tones close in frequency play simultaneously, your ear perceives a slow amplitude oscillation called beating, at a rate equal to the difference between the two frequencies. Two sines at 440 Hz and 442 Hz beat 2 times per second; 440 and 445 beat 5 times per second. Beats are the physical sum-and-difference of the two waves: when their peaks align you hear a louder moment, and when they cancel you hear a quieter moment. Piano tuners listen for beats between two strings of the same note to tune them in perfect unison (zero beats) or controlled detuning (a few beats per second for chorus effect). Beating is also the basis of binaural hearing: separate tones in each ear at small offsets can produce phantom "binaural beats" perceived inside the head.

How do dBFS, dBSPL, dBV, and dBu relate to tone levels?

Each dB unit references a different baseline. dBFS (dB Full Scale) is digital: 0 dBFS is the maximum the system can represent without clipping; everything is negative. dBSPL (Sound Pressure Level) is acoustic: 0 dBSPL is the threshold of human hearing (20 µPa), conversation is around 60 dBSPL, a rock concert 110 dBSPL, pain threshold 120-130 dBSPL. dBV references 1 V RMS; consumer line level is -10 dBV (about 316 mV). dBu references 0.775 V RMS; pro line level is +4 dBu (about 1.23 V). When you set the tone generator to -20 dBFS, the actual SPL in the room depends on your interface output level, amplifier gain, and speaker sensitivity — calibrate with an SPL meter before relying on absolute loudness.

What is a sweep, chirp, or MLS signal and when should I use one?

A swept sine (often called a sine sweep or chirp) continuously varies the frequency from a start to an end value over time — linear sweep (Hz/sec) for low-frequency analysis, logarithmic sweep (octaves/sec) for full-range room measurement and impulse response capture. Engineers convolve the recorded sweep with its inverse to compute a room or speaker impulse response that reveals reflections, decay times, and frequency response in one capture. MLS (Maximum Length Sequence) is a pseudorandom binary signal that sounds like white noise but cross-correlates to an impulse, allowing similar measurements with better noise immunity. Pink noise pulses are simpler and great for quick A/B checks. Use sweep + convolution for IR capture, MLS for noisy environments, and pure tones for steady-state distortion or feedback hunting.