a) Random noise which has equal energy per octave throughout the audio spectrum. b) A type of noise whose amplitude is inversely proportional to frequency over a specified range. Pink noise is characterized by a flat amplitude response per octave band of frequency (or any constant percentage bandwidth), i.e., it has equal energy, or constant power, per octave. Pink noise can be created by passing white noise through a filter having a 3 dB/octave slope.