Click here to purchase the entire book in PDF format. Pink Noise Pink noise is noise that has an equal amount of energy per octave. This means that there is less energy per Hz as you go up in frequency (in fact, there is a power loss of 50% (or a drop of 3.01 dB) each time you go up an octave) This is used because it sounds relatively ``equal'' in distribution across frequency bands to us. Another way of defining this noise is that the power of each frequency $f$ is proportional to $\frac{1}{f}$.