White and Pink Noise
White noise is sound that contains every frequency within the range of human hearing (typically 20Hz - 20kHz) in equal amounts.
Many perceive this sound as having more high-frequency content than low, even though this is not the case. This occurs because each successive octave has twice as many discrete frequencies as the one preceding it. E.g. from 50Hz to 100Hz, there are fifty different frequencies. In the next octave
i.e. from 100Hz to 200Hz, there are hundred frequencies.
Pink noise is a variant of white noise that has been filtered to reduce the volume at each octave in order to compensate for the increase in the number of frequencies per octave. An octave is any band of audio frequencies where the highest included frequency is exactly two times
the lowest included frequency.
Each octave is reduced by 6dB, resulting in a noise sound wave that has equal energy at every octave.