What is pink noise?

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?

If you ever heard one of her albums, you would know.

Alcides - your pink/white noise analysis is correct, but you're off by an octave on the piano's low end. The standard 88-key piano goes down to ~28Hz, also the 440Hz A is above middle C, not below.