Pink noise has a power spectrum that decreases 3 dB per octave — its energy per octave is constant. This matches human hearing better than white noise (equal energy per frequency), making it ideal for: speaker measurement and room correction (sine sweeps are more precise but pink noise is faster), equal-loudness testing, and sound masking for sleep or concentration.
When calibrating monitors to a reference level (typically 79–85 dB SPL at the listening position), pink noise is played at −20 dBFS through each speaker individually, and the SPL meter reading is adjusted until all speakers match.