White Noise (more accurately known as "sound masking") is based on the phenomenon that when "low level background noise" is added to an environment, intruding speech and noises are less intelligible. The term "white noise" is widely used when referring to speech privacy or sound masking systems, although these systems don't actually use white noise.
The technology behind sound masking came out of the realization by scientists and engineers that "oral privacy" is actually a simple matter of making speech unintelligible. That is, if each of us can't understand what the other is saying, we have effectively established oral privacy - even though we may still be able to see and, to some extent, hear each other.
Sound masking "fills in" the sound spectrum around you with barely perceptible "low level noise", so that speech is rendered unintelligible. It's actually designed to sound like typical office air conditioning noise, so that you won't notice it. In other words, it's a gentle "whooshing" sound.
http://www.speechprivacysystems.com
