Free Online Tone Generator
Test your hearing range · Tune your guitar · Explore sound waves
A4
Guitar tuning ▸
⚠ High frequencies can be uncomfortable at loud volumes.
Second tone: 659.26 Hz (Perfect 5th)
🎧 Requires headphones for binaural effect.
Beat frequency: 10 Hz
No files, no uploads — runs entirely in your browser.
What Is a Tone Generator?
A tone generator produces a pure audio signal at a specific frequency and waveform. Musicians use it to tune instruments to concert pitch (A4 = 440 Hz). Audio engineers test speakers, headphones, and room acoustics by sweeping frequencies from 20 Hz to 20 kHz. Curious listeners discover their hearing range — most adults can't hear above 16-17 kHz.
Our tone generator runs entirely in your browser using the Web Audio API. The frequency is precise to hundredths of a hertz, and you can switch between four waveform shapes to hear how harmonics change the timbre of a sound. Add a second tone for ear training intervals or binaural beats.
How to Use the Tone Generator
- Choose a frequency — use the slider, type a value, or pick a preset (A4 = 440 Hz, C4 = 261.63 Hz, or any guitar string).
- Select a waveform — sine for pure tones and tuning, square for retro sounds, sawtooth for rich textures, triangle for soft tones.
- Press Play — adjust volume and frequency in real time. The waveform visualization updates live.
Understanding Waveforms
Sine — clean
The purest tone — just the fundamental frequency, no harmonics. Smooth and clear. Used for tuning, hearing tests, and calibration.
Square — retro
Odd harmonics only (1st, 3rd, 5th...). Sounds hollow and electronic — the classic 8-bit video game sound.
Sawtooth — buzzy
All harmonics present — the richest, most complex sound. Like a buzzing string or a brass instrument.
Triangle — soft
Odd harmonics that fade quickly — softer and warmer than square. Sounds flute-like and gentle.
Musical Note Frequencies
| Note | Frequency | Context |
|---|---|---|
| C4 | 261.63 Hz | Middle C |
| E4 | 329.63 Hz | Guitar high E string |
| A4 | 440.00 Hz | Concert pitch standard |
| A4 | 432.00 Hz | Alternative tuning |
| A4 | 415.00 Hz | Baroque tuning |
Formula: freq = 440 × 2(n−69)/12 where n is the MIDI note number.
Practical Uses
- Instrument tuning — use A4 (440 Hz) or guitar presets for quick reference pitches
- Speaker testing — sweep from 20 Hz to 20 kHz to check your speaker's frequency response
- Hearing test — find the highest frequency you can hear (typically drops with age)
- Sound education — visualize how different waveforms look and sound in real time
- Ear training — use Interval mode to practice recognizing musical intervals
Frequently Asked Questions
What frequency is concert pitch?
A4 = 440 Hz, the international standard since 1955. Some orchestras tune slightly higher (441-443 Hz) for a brighter sound. Alternative tunings include 432 Hz and Baroque pitch at 415 Hz.
What are the different waveforms?
Sine is a pure tone with no harmonics. Square adds odd harmonics for an electronic sound. Sawtooth includes all harmonics for the richest timbre. Triangle has quiet odd harmonics for a soft, flute-like tone.
Can I use this to tune my guitar?
Yes. Use the guitar tuning presets: E2 = 82.41 Hz, A2 = 110 Hz, D3 = 146.83 Hz, G3 = 196 Hz, B3 = 246.94 Hz, E4 = 329.63 Hz. Play a string and match the pitch.
What is the human hearing range?
Humans can hear from about 20 Hz to 20,000 Hz. High-frequency sensitivity declines with age — most adults lose frequencies above 16-17 kHz by age 30.
Why does the volume decrease at high frequencies?
For safety. High frequencies are perceived as louder and can cause discomfort or hearing damage at full volume. The generator automatically caps the gain at higher frequencies.
What are binaural beats?
When two slightly different frequencies play in separate ears (e.g., 400 Hz left, 410 Hz right), the brain perceives a pulsing at the difference — 10 Hz. This requires headphones because each ear must hear only its own frequency.
Can this damage my speakers?
Very low frequencies (20-40 Hz) at high volume can stress small speakers beyond their excursion limit. Use moderate volume when exploring the low end, especially on laptop or phone speakers.
Is my data sent to a server?
No. The tone is generated entirely in your browser using the Web Audio API. Nothing is uploaded, recorded, or transmitted.