Pink Noise

What is pink noise?

Pink noise refers to noise where the sum of the amplitude of the frequencies in each octave is equal. In contrast to white noise, where the amplitude is the same for all frequencies, the noise volume  of pink noise gets 3 dB quieter per octave.

Noise in general synthesis talk is everything you hear that is not a part of the signal, you might have heard the term noise to signal ratio. Noise can be described as a speaker buzzing at maximum volume or even the white specks on old televisions.

In most design and technology areas, noise is considered something that should be reduced and limited. However, music producers have found a way to use and take advantage of noise in interesting and creative ways.

Noise is referred to in colors, with the two main colors being pink and white. Pink noise is based around octaves and how it contains equal energy per octave, it is described as a much fuller sound with an increased low end.

If you take a 50Hz sound, it would need to double in frequency to reach 100HZ for the next octave, whereas a 500Hz sound would need to double to 1000Hz for it to reach the next octave. The two ranges of frequencies are very different, 50Hz compared to 500Hz.

Pink noise takes into consideration all frequencies of the spectrum, the high frequencies will be played at a lower volume than the low frequencies, giving the sound a more rounded feel to it. Pink noise takes into consideration the highs and lows of the octave range.

Pink noise is often used as a reference when mixing and balancing a song, called Pink Noise Mixing. This is because it better follows the acoustics of the human ear. Human ears are designed to hear sounds similar to pink noise, with the lease amount of sensitivity in the low-end, and the most sensitivity in the high-end.