Blue noise

Blue noise is the mirror image of pink noise. Its power rises 3 dB per octave, so each octave carries twice the energy of the one below it. That tilts the spectrum toward the highs, giving a thin, airy hiss that is brighter than white noise. Also called azure noise, it is handy in a modular system for hi-hats, steam and air textures, and as a fast, jittery modulation source with very little slow drift. It is also used in digital dithering, where it pushes quantization error up into frequencies the ear is less sensitive to.