Free Tool
Audio Signal Generator
Sine waves, white noise, pink noise, brown noise, blue noise, violet noise, frequency sweeps, and polarity check. All generated in real time by the Web Audio API - no files, no downloads. Identical to what professional audio generators output.
Tip: start at low volume. The 1 kHz sine wave at −12 dBFS is the standard reference test signal. Pink noise at −18 dBFS is the level-matching reference most calibration tools use.
About the noise colors
- White noise
- Equal energy at every frequency. Sounds like TV static or heavy rain. Used for masking ambient noise and speaker frequency response testing.
- Pink noise
- Equal energy per octave (-3dB/octave slope). Perceptually "flat" - the closest noise to music in spectral balance. The standard for room acoustic measurements.
- Brown noise
- -6dB/octave slope. Heavy bass emphasis - often described as a waterfall or deep rumble. Very popular for sleep and focus.
- Blue noise
- +3dB/octave slope. High-frequency emphasis - sounds bright and hissy. Used in dithering algorithms to push quantization noise out of the audible band.
- Violet noise
- +6dB/octave slope. Extreme treble emphasis. Rarely used in audio but appears in some dithering applications and tinnitus research.
Frequency landmarks worth remembering
Pin these tones to your ear. Sweep the generator above between any two of them and you start to hear the structure of the audible band - and where every "warm," "bright," "muddy," or "harsh" complaint actually lives.
| Frequency | Landmark | What it does in music |
|---|---|---|
| 20 Hz | Lower hearing limit | Felt rather than heard. Pipe organ pedal, EDM sub. |
| 41.2 Hz | Bass guitar low E | The bottom of most rock recordings. |
| 50 / 60 Hz | Mains hum | Ground loop frequency. Listen for it on quiet passages. |
| 82.4 Hz | Guitar low E | Body / chest of the rhythm guitar. |
| 200-250 Hz | "Muddy" zone | Boomy male vocals; cup/proximity effect on mics. |
| 440 Hz | Concert pitch A | Tuning standard. Where instruments meet. |
| 1 kHz | Reference tone | SPL meter calibration. Voice intelligibility centre. |
| 3-4 kHz | Ear sensitivity peak | Fletcher-Munson minimum. Sibilance starts here. |
| 6-10 kHz | Sibilance band | "S" and "T" consonants. Bright cymbals. |
| 15 kHz | Adult upper limit | Most adults can't hear above this; kids reach 18 kHz+. |
| 20 kHz | Theoretical upper limit | The Nyquist target. Few adults hear it cleanly. |
FAQ
Audio signal generator FAQ.
What you can test with sines, sweeps, and the noise colours - plus safe SPL ranges for measurement work.
What can I do with an audio signal generator?
Test speakers and headphones with sine sweeps, room behaviour with pink noise, channel matching with mono-vs-stereo tones, polarity with a polarity-check signal, and DAC linearity with low-level test tones. It is the swiss army knife of audio measurement - frequency response, distortion, phase, channel balance, all from one page.
What is the difference between white, pink, brown, blue, and violet noise?
White noise has equal energy per Hz; pink noise has equal energy per octave (the standard for room measurement); brown (Brownian) drops 6 dB per octave for deep low-end testing; blue rises 3 dB per octave; violet rises 6 dB per octave. Pink and brown are the most useful for audio work; the others appear in DSP testing and synth design.
How loud should test tones be when measuring speakers?
Start at -20 dBFS in the player and adjust the amplifier so a 1 kHz sine measures around 80 dB SPL at the listening position. Sweeps and pink noise can stay at the same RMS. Never go above 95 dB SPL for sustained tones - it is not pleasant for ears or speakers.
Does the signal generator work for ear training?
It can, but the dedicated frequency-training tool is built for that purpose with adaptive difficulty and scoring. Use the signal generator when you need a specific tone or sweep on demand; use the trainer when you want guided practice and progress tracking.