What is pink noise, and what it's for
Why pink noise sounds different from white noise, and when to use each one.
What pink noise actually is
White noise carries equal energy at every frequency. Human hearing doesn't perceive every frequency with the same sensitivity — we're more sensitive to high frequencies than low ones — so white noise ends up sounding more "hissy" than its name suggests.
Pink noise corrects for that: energy drops as frequency rises (roughly 3 dB less per octave), so each octave contributes equal perceived energy. The result is a deeper, more even sound that most people find more comfortable to listen to for long stretches.
What it's used for in practice
It's commonly used to mask distracting background sounds (traffic, an open office, a noisy neighbor), as background for sleep or focus, and in professional audio to calibrate sound systems and test speaker frequency response, since its energy distribution better matches how we actually hear music than white noise does.
Pink noise vs. brown noise
Brown noise takes the same idea further, with an even steeper drop in high frequencies (6 dB per octave), sounding deeper and more "engine-like." Neither is objectively better — it comes down to personal preference and how sensitive someone is to high frequencies.