Blue noise
Whereas most of the sounds described on this list are pleasant to our brains, not all of them are the same. Blue noise, the black sheep in the noise family, is composed of high-pitched sounds and resembles the hiss of a kinked water hose.
Because of its harsh sound, blue noise isn’t recommended if you’re trying to get a good night’s sleep. Still, it does a great job at masking outside noises, such as a city’s busy streets, which may help you focus while working or studying for a test.
