White Noise

In signal processing, white noise is a random signal having equal intensity at different frequencies, giving it a constant power spectral density. --Wikipedia.

Pink Noise

Pink noise or 1⁄f noise is a signal or process with a frequency spectrum such that the power spectral density (power per frequency interval) is inversely proportional to the frequency of the signal. In pink noise, each octave interval (halving or doubling in frequency) carries an equal amount of noise energy. Pink noise is one of the most common signals in biological systems. --Wikipedia.

Brown Noise

In science, Brownian noise, also known as Brown noise or red noise, is the kind of signal noise produced by Brownian motion, hence its alternative name of random walk noise. --Wikipedia.