There are several different types of noise and they're categorized by color. The most common are white, pink and brown noise. Each defined by the way it distributes power to frequencies across the audible spectrum.
Here's what that means. White noise distributes power to every frequency equally. .
. but it tends to sound harsh to us because the shape of our ears makes us more sensitive to higher frequencies and lower ones. And that makes them sound louder even though the power distribution is equal.
Pink noise adjusts for this, boosting the harder to hear low frequencies and then reducing power proportionally as frequency as frequency goes up to give each octave of noise approximately equal energy. This ends up sounding more balanced to our ears even though it's actually skewed. Brown noise takes this idea even further.
. . resulting in a low, ocean-like rumble that a lot of people find relaxing.
