brown noise (also sometimes called red noise) is the deeper cousin of white noise, with a sound profile that emphasizes lower frequencies and downplays higher frequencies. Natural brown noise sounds like the roar of a river rapids, heavy rains and distant, rumbling thunder, which many find pleasing to the human ear.
This type of noise is named not only for a color, but also for Scottish scientist Robert Brown.
In the 19th century, Brown observed pollen particles moving randomly in water and devised a mathematical formula to predict these movements. When you use this random formula to generate electronic sound, you get a bass-heavy noise profile.
White noise, on the other hand, covers all frequencies, from low-frequency bass notes to high-frequency bells. Effectively masks sound inconsistencies, helping you fall into a peaceful sleep.
Natural events such as pouring rain or a gentle breeze rustling through the trees can be considered forms of white noise.
Pink noise: a soft alternative
However, your options are not limited to brown and white noise. There’s also pink noise, which could be the answer to quality sleep. A Northwestern University study linked pink noise to deeper sleep and better word memory in older adults.
Pink noise is similar to white noise but leans more towards low and mid tones, similar to sounds like moderate rain or ocean waves. Those who prefer lower-pitched sounds may find pink noise more pleasant to the ear.