Glossary definition of 'Pink noise'

Random noise whose energy is constant per octave band. When viewed as an FFT spectrum on a logarithmic frequency axis, its level drops at 3dB per octave due to the linearly spaced analysis frequency intervals. When viewed on a real time analyzer using fractional octave bands, it gives a flat line.

True pink noise is impossible to create since its amplitude tends to infinity as the frequency tends to zero. Practical pink noise is therefore always band limited and is usually generated by filtering white noise.

Pink noise is useful for testing audio equipment, particularly loudspeakers, as it is more representative of the energy spectrum of music than white noise. Loudspeakers typically have far higher power handling at low frequencies than high frequencies and environmental noise often also has a "pink" character. Using pink noise or pink weighted multi-tones allows the use of higher levels of signal with reduced risk of destroying HF drivers while giving a better signal to noise ratio over background noise.

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