Online Audio & Media Tools: Tone Generator, Metronome, White Noise & More
The modern web browser is a capable audio workstation. Without installing any software, you can generate pure sine waves, practice with a click track, record your voice, detect the pitch of an instrument, or fill a room with white noise for focus or sleep. Understanding how each tool works helps you get the most from it.
How Tone Generators Work
A tone generator uses the Web Audio API's OscillatorNode to synthesise audio signals in real time. You select a frequency (in Hertz) and a waveform type — sine, square, triangle, or sawtooth — and the browser generates the sound digitally through your speakers or headphones.
Common uses include:
- Testing speaker frequency response (audibility range for typical human hearing is 20 Hz–20,000 Hz)
- Tuning acoustic instruments by ear using a reference pitch
- Checking hearing at specific frequencies
- Producing test tones for audio equipment calibration
The Online Tone Generator lets you dial any frequency and waveform instantly. The Pitch Detector & Instrument Tuner does the reverse — it listens via your microphone and identifies the fundamental frequency of any sound, displaying the nearest musical note and how many cents sharp or flat you are.
Using an Online Metronome
A metronome produces an audible click at a steady tempo, expressed in beats per minute (BPM). At 60 BPM there is exactly one click per second; at 120 BPM, two clicks per second.
Practice tips:
- Start 10–20 BPM below your target tempo and only increase when a passage is clean.
- Practice individual bars in isolation before stringing them together.
- Use subdivisions (eighth or sixteenth notes) to lock in faster passages.
The Online Metronome supports time signatures, accent patterns, and tap-tempo input so you can match the tempo of a recording by tapping along.
White Noise, Pink Noise, and Binaural Beats
These are related but distinct types of audio:
| Type | Spectral Character | Common Use |
|---|---|---|
| White Noise | Equal power per frequency | Sleep, focus, masking distractions |
| Pink Noise | Equal power per octave (−3 dB/octave) | Sleep, audio testing, naturalistic sound |
| Brown Noise | Power decreases at −6 dB/octave (deeper rumble) | Deep focus, tinnitus relief |
| Binaural Beats | Two slightly different frequencies, one per ear | Focus, relaxation, meditation |
The White Noise Generator produces broadband noise suitable for masking office chatter or helping infants sleep. The Binaural Beat Generator plays a slightly different frequency in each ear — the brain perceives a third "beat" at the difference frequency. For example, 200 Hz in the left ear and 210 Hz in the right produces a 10 Hz binaural beat, associated with relaxed alertness (alpha brainwave range).
Note: Binaural beats require stereo headphones to work — they do not function through speakers.
Recording and Visualising Audio
The Voice & Audio Recorder captures audio directly from your browser using your microphone, then lets you download the recording as a file — no account or app required. The Live Audio Visualizer renders your microphone input as a real-time waveform or frequency spectrum (FFT), useful for understanding sound characteristics, checking microphone pickup, or simply enjoying a visual display of music.
The Screen Recorder captures your display and optional microphone audio together — useful for creating tutorials, recording presentations, or documenting software bugs.
Text to Speech
The Text to Speech tool converts written text to spoken audio using your browser's built-in Speech Synthesis API. Available voices depend on your operating system and browser. Uses include proofreading by ear, accessibility testing, language pronunciation practice, and creating voiceover drafts.
Common Mistakes
- Listening to loud tones for extended periods. Pure tones at high volume can cause ear fatigue or damage. Keep test tones at comfortable listening levels and limit exposure time.
- Using a tone generator without headphones for pitch-matching. Speaker bleed into a microphone creates feedback. For pitch detection with the Pitch Detector, use headphones or lower the reference volume.
- Expecting binaural beats to work without headphones. Playing binaural beats through speakers merges both channels before they reach your ears, eliminating the spatial effect that creates the perceived beat.
- Recording in a noisy environment. The Voice & Audio Recorder picks up all ambient sound. Record in a quiet room, close to the microphone, with doors and windows shut.
Frequently Asked Questions
What frequency is middle A (A4)?
A4 is 440 Hz, the standard tuning pitch used by orchestras worldwide (concert pitch). Some orchestras use A4 = 442 Hz or higher for a brighter sound.
Can white noise damage your hearing?
At safe listening volumes (below 85 dB SPL), white noise poses no hearing risk. Problems arise from sustained high-volume exposure. Use the audio at a comfortable level — you should be able to hold a normal conversation over it.
Do binaural beats actually work?
Research on binaural beats is preliminary and mixed. Some studies report modest effects on relaxation and attention; others find no significant difference from control conditions. They are generally safe for most people but should not be used while driving or operating machinery.
What is the difference between a waveform visualizer and an FFT visualizer?
A waveform visualizer shows amplitude over time — the shape of the sound wave. An FFT (Fast Fourier Transform) visualizer shows the frequency content — how much energy is present at each frequency. The Live Audio Visualizer typically offers both views.