Rain Sounds
White noise: the bright hiss
White noise has the same power at every frequency, from the deepest bass to the highest treble. That sounds fair, but each octave up holds twice as many frequencies as the one below it, so the high end carries most of the energy.
The result is a bright, sharp hiss, like a radio tuned between stations or a fan on high. It is very good at hiding speech, and some people find it harsh.
Source: Wikipedia: Colors of noise.
Pink noise: softer and balanced
Pink noise turns the power down by about 3 dB for every octave you go up. That evens it out so every octave carries the same energy.
Our ears hear pitch in octaves, so pink noise sounds balanced rather than hissy. People often compare it to steady rain or wind in leaves.
Source: Wikipedia: Colors of noise.
Brown noise: the deep rumble
Brown noise drops faster, by about 6 dB per octave, so most of its energy sits in the low notes. It sounds like a distant waterfall, heavy surf or the hum inside a plane.
The name has nothing to do with the colour. It comes from Brownian motion, the random jiggling of tiny particles described by the botanist Robert Brown, because the signal wanders in the same random way. It is also called red noise.
Source: Wikipedia: Colors of noise.
Green noise: the middle
Green noise is not a scientific term like the other three. It is a popular name for noise centred on the middle of the range, around 500 Hz, with the deep lows and the high hiss turned down.
Because there is no standard, every app makes it a little differently. Ours is pink noise with both ends rolled off and the middle lifted.
Source: Wikipedia: Colors of noise.
Which one should you choose?
There is no right answer, only the one that suits your ears and your room. A simple way to choose: start with brown. If it sounds muffled, try pink. If you need to cover voices, try white, at a low volume.
If you use noise for sleep, keep it quiet. The research on noise as a sleep aid is still limited: a 2021 review of 38 studies rated the evidence as very low quality.
Source: Riedy et al., “Noise as a sleep aid: a systematic review”, Sleep Medicine Reviews, 2021.
What you're hearing
- White noise
- Steady rain (off to start: raise it to add it)
Most sounds here are generated live in your browser, so nothing long downloads before it plays. The full mixer adds more sounds, other versions of each, and real recordings.
Questions
- Is brown noise the same as red noise?
- Yes. Both names describe noise that falls by about 6 dB per octave. Source: Wikipedia: Colors of noise.
- Are there other colours of noise?
- Yes. Blue noise rises by about 3 dB per octave and violet noise by about 6 dB, so both sound even brighter than white. They are rarely used for listening, so they are not in the player. Source: Wikipedia: Colors of noise.
- Which noise colour is best for focus?
- It is personal. Many people find brown or pink noise easier to work with for a long time, because they are less sharp than white. Try each one for a few minutes at a low volume.
- Is it free?
- Yes, for now everything is free, the real recordings included. There is nothing to sign up for, nothing to install and no ads. Later some real recordings may move to a paid option; the sounds made in your browser will stay free.