What is pink noise?

Pink noise is equal energy at any given octave. White noise is equal energy at any given frequency.

The result is that white noise sounds more like high frequency noise, and pink noise sounds like full range noise.

Think of it this way. An octave represents a doubling of frequency (40Hz is an octave higher than 20Hz. 14,000Hz is an octave higher than 7000Hz etc.)

As you look at that, think about how many more frequencies are contained within any given octave as you go up the musical scale.

Concert A (a minor third below middle C on the piano) is equal to 440Hz. The lowest note on the piano (excluding some Bosendorfers) is three octaves below that, or 55Hz. If we count in whole integers, there are only 385 frequencies between those three octaves. Three octaves ABOVE concert A resonates at 3,520Hz. If we count in whole integers again, there are 3080 frequencies between concert A, and the A three octaves above it.

If each one of the 3,465 frequencies implied in the above paragraph has the same power when they are all played at once, we will hear the higher frequencies as being louder, because there are more of them per any given octave as you go up the scale. White noise

If you devide up those frequencies into octaves, and compensate for the doubling of energy that is inhearant in white noise by giving as much energy to the octave between the lowest note of the piano ((A1-A2) 55-110Hz) as you would to the higest octave of the piano ((C7-C8) 2093.04 - 4186.08Hz,) you get Pink Noise.

hope this helps

the name pink noise comes from the fact that the noise is skewed with more power towards the low frequencies... i.e. the redish or pink equivelant in the visual spectrum.

White light has equal energy per frequency as well.

Pink noise being equal energy per octave (or even more importantly equal energy per one-third octave) divides the frequency spectrum in a manner similar to the human ear. One-third octave spectrum analysis and equalization often results in a corrected spectrum that is generally pleasing perceptually (particularly in sound reinforcement applications).

Ok, this is fascinating. Since we've gotten the attention of folks who genuinely know their stuff, I've got one more that's been puzzling me -- "brown noise."

I'd never heard of this before geting thay Ayre burn-in disk, which has tracks of white, pink and brown noise (as well as some full frequency sweep tones). What am I getting with the brown noise besides an apparently deeper yet tone from the pink noise and a whole lot more exercise for the bass drivers?

is "brown noise" and fart the same thing?