Noise

Ever wonder what makes up the different types of Noise offered on synths? David Hillel Wilson, curator of the New England Synthesizer Museum and host of Synth Museum posted the following on AH. Title link takes you to the Synth Museum website.

"OK Here is the theory. White noise has every possible sine wave all at the
same volume.
Unfortunately, since the Human ear hears frequencies logarithmically, the
pure randomness
of white noise sounds high pitched to us. Since we hear twice as many
frequencies in any
octave as we do in the octave just below it, to create a noise that "sounds"
right requires
that the amplitude of the noise drop off at 1/2x per octave, or 3dB/Oct.
This is the definition
of Pink noise. Further low-pass filtering can make red noise, while high
pass filtering would
make blue noise. There are, to the best of my knowledge, no exact
definitions for colors
of noise other than white and pink. The "Color" idea comes from optics:
Light containing
all colors in equal strengths is seen by the Human eye as "white". If we
remove the higher
frequency (shorter wave length) lights, the color literally shifts to pink,
hence the name."

David Hillel Wilson
Curator
New England Synthesizer Museum