Different spreads are given different colour names, including white, pink, brown, blue, violet and grey. Here's how they differ from each other, and what they tend to be used for.

White, brown, and pink noise are the colors of noise that are most commonly known and studied. ... For instance, violet noise is when the high-frequency sounds are made louder.

Besides white, pink, and brown noise, there are other color noises that aren’t related to sleep. ... Violet noise. Also called purple noise, it’s the opposite of brown noise.

Over the last 20 years, scientists have uncovered evidence that immersive sounds like white, brown and pink noise may help the brain to focus, sleep or relax — especially for people with A.D.H.D ...