Blue (Azure) Noise

Definition

Blue Noise

Blue noise is a random signal that has been filtered in order to generate higher energies at higher frequencies. Its power density is proportional to the frequency and increases by 3 dB per octave.

Blue noise is also referred as azure noise. These names come from visible light that turns into these colors when a similar spectral distribution is applied.

In other words...

Blue noise packs a lot of energy in the highest frequencies: each octave packs as much energy as the two octaves below it!

Perception

White noise, which is spectrally flat, seems already very bright to our auditory system. Blue noise will sound even brighter, with bass frequencies totally missing.

Applications

In audio applications, blue noise represents a good candidate for dithering, a process in which noise is intentionally applied to a signal in order to randomize quantization errors during bit depth conversions. This process is referred as dithering or noise shaping

In healthcare applications, blue noise is sometimes used to mask tinnitus, a buzzing, ringing, or whistling in your ear, occurring without any stimulus.

Credits

Our blue noise sample file has been generated using wavTones' professional grade Noise Generator.

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