Noise color is determined by the frequencies present. Simply put, white noise is comprised of random and equal amounts of frequencies from the entire sound spectrum. This is why it is so effective at masking just about every external sound. The reason that this works is simple. Audiology research has discovered that the human ear can only process a given number of sound frequencies at once. White noise machines create a sound pattern utilizing all available frequencies. This causes other noises to fade into the background and become less noticeable, preventing them from disturbing your sleep. Common benefits of white noise include: Sound masking and cancellation, Improved concentration, Sleep promotion.