From: Wagner Lipnharski
>
> Once at the new IBM building in Curitiba city (Brazil), it was installed
> white noise generators to blast down room to room human voice.  White
> noise is something your hearing can ignore, but it takes down a great
> level of ambient sounds too.

The same technique used to relieve tinnitus. The patient is fed white
noise, which they soon become used to and ignore. As the volume of the
white noise is gradually reduced over a period of time, it "takes" the
tinnitus with it as the patient's auditory system adjusts