Developer Thomas Glendinning has released Binaural Beat Generator, a free Mac application, available in VST and AU plugin formats, that lets you explore binaural beats.
Binaural beats are a psychoacoustic effect that occurs when you listen to sounds of two slightly different pitches through headphones. For example, if a 300 Hz tone is played in one ear and 310 Hz in the other, then a binaural beat of the difference, 10 Hz, is heard.
Some ascribe physiological and psychological effects to binaural beats, calling them ‘digital drugs’.
Binaural Beat Generator is a free and open source app, downloadable from SourceForge.