Noise color describes the spectral distribution of random audio — white is flat, pink is 3dB/octave rolloff

Noise is signal with a random waveform, and its ‘color’ describes how energy is distributed across frequency. White noise has equal energy per unit bandwidth — its spectral graph looks flat — so high frequencies sound perceptually emphasized because there are more frequency bins there. Pink noise has equal energy per octave, meaning it rolls off the high end at approximately 3 dB per octave, which matches human perceived ‘flatness’ better. Pink noise is often used as a reference signal in acoustics and mastering. Brown noise rolls off even more steeply. Knowing noise colors matters in sound design (percussion synthesis uses filtered noise) and in audio measurement/testing.

Examples

In a drum machine, synthesize a snare by filtering white noise with a narrow bandpass to create the characteristic ‘snap.’ Compare white vs pink noise through headphones: white sounds harsh/hissy, pink sounds more balanced.

Assessment

Explain the difference between white and pink noise in terms of energy distribution. Then say which one you would use as a flat-sounding test signal for tuning a PA and why.