White noise generator

Three kinds of noise, generated in the page rather than streamed. White is flat across all frequencies and sounds hissy; pink falls off with frequency and sounds like rain; brown falls off faster and sounds like a waterfall or distant traffic.

The colours are precise terms, not marketing. White noise has equal power at every frequency, which puts a great deal of energy in the high range where hearing is most sensitive — hence the hiss. Pink noise drops 3 dB per octave, giving equal power per octave, which is much closer to how natural sounds are distributed and why it sounds like rain. Brown drops 6 dB per octave and is dominated by the low end. For masking speech through a wall, pink or brown works better than white, because speech energy is low and mid-range and covering it with hiss just adds a second thing to hear.