The subject of today’s post is three kinds of noise you can generate easily in Audacity or a similar program: white noise, pink noise, and brown noise. Everyone has heard of white noise. White noise is a combination of all audible audio frequencies. It is often used in the production of electronic music because it can cut through all other audio frequencies. The sirens on some emergency vehicles use white noise because it can be heard over background noise, making these vehicles easier to locate.
You may not have heard of pink noise. It drops off by 3 dB per octave as frequencies climb, with equal amplitude across each wave. Since lower frequencies have more power than higher frequencies, pink noise sounds more like a roar than a hiss. It is sometimes generated by analog synthesizers. Brown noise is also referred to as Brownian noise and red noise. The term “brown” comes from Brownian motion and does not refer to the color brown. Robert Brown discovered Brownian motion. It decreases in amplitude by 6 dB for as frequencies increase, resulting in a heavy bass sound.
The table below is a graphical representation of these three kinds of noise, which I generated in Audacity.