Interactive demo
Colors of Noise
Noise gets its color from its spectrum, by analogy with light: white noise has the same power at every frequency, pink and brown noise are dominated by low frequencies, blue and violet noise by high ones.
Start with a low volume, blue and violet noise sound sharp. The dashed line is the ideal slope of the selected color.
Controls
Sound
Legend
- White
- Pink
- Brown
- Blue
- Violet
1. What the color means
The spectrum shows how much power a signal has at each frequency. On a log–log scale, colored noise is a straight line: the power is proportional to the frequency raised to a power β, with β = 0 for white, −1 for pink, −2 for brown, +1 for blue and +2 for violet noise.
2. Shaping the spectrum
All five start as the same white noise. A fast Fourier transform (FFT) splits it into frequencies, every frequency is scaled so that its power follows the slope, and the inverse transform turns it back into a signal. The image is made the same way in 2D.
3. Where they are used
Pink noise sounds balanced to our ears and is used to test loudspeakers and rooms. Brown noise, named after Brownian motion rather than the color, rumbles like a distant waterfall. Blue noise has no clumps, which makes it ideal for dithering and for spreading out sample points.