What is green noise?

Green noise is a type of noise signal that has a power spectral density that decreases in power by 3 decibels per octave with increasing frequency. It falls between white noise, which has a flat power spectral density, and pink noise, which decreases in power by 3 decibels per octave with decreasing frequency.

Green noise is often described as having a smoother and more natural sound compared to white noise, making it popular for use in audio applications such as sound masking, audio testing, and relaxation therapy. It is also used in scientific research to study the frequency response of systems and to model the natural variations in environmental noise.

Green noise can be generated digitally using algorithms or created by filtering white noise through a specific equalization curve. It is sometimes referred to as "emerald noise" due to its association with the color green.