| Colour |
|
Description |
| Blue |
 |
Or azure noise, the power density increases 3 dB per octave with increasing frequency (density proportional to f) over a finite frequency range. |
| Brown |
|
Or red or Brownian noise, the power density decreases 6 dB per octave with increasing frequency (density proportional to 1/f 2) over a frequency range which does not include DC. |
| Green |
|
A really long term power spectrum averaged over several outdoor sites, like pink noise with a hump added around 500 Hz. |
| Grey |
|
Random white noise subjected to a psychoacoustic equal loudness curve (such as an inverted A-weighting curve) over a given range of frequencies. |
| Orange |
|
A finite power spectrum with a finite number of small bands of zero energy dispersed throughout a continuous spectrum. |
| Pink |
|
The frequency spectrum is linear in logarithmic space, it has equal power in bands that are proportionally wide. The power density falls off at 10 dB/decade (-3 dB/octave). |
| Purple |
|
Or violet noise, the power density increases 6 dB per octave with increasing frequency (density proportional to f 2) over a finite frequency range. |
| White |
|
The signal has equal power in any band of a given bandwidth (power spectral density). |
