The key difference
Both colors roll off the high frequencies, but by different amounts. Pink noise reduces treble by 3 dB per octave for a natural, rain-like balance. Brown noise cuts it twice as steeply, at 6 dB per octave, so it is much deeper and more rumbly, like a waterfall. Pink sits in the middle of the spectrum; brown sinks into the bass.
- Pink noise: balanced, natural, rain-like; strongest deep-sleep research.
- Brown noise: deeper and warmer; great if bright sound bothers you.
Which should you choose?
Choose pink noise if you want a natural, balanced sound with research behind it for deep sleep. Choose brown noise if you love a deep rumble or find any brightness distracting. For focus, brown often wins; for research-backed sleep, pink has the edge. Test both and trust your ears.