> ... creating an effect familiar to most musicians, who rely on it for ensuring that their instruments are in tune. I believe you are referring to acoustical

> ... creating an effect familiar to most musicians, who rely on it for ensuring that their instruments are in tune. I believe you are referring to acoustical beats. http://en.wikipedia.org/wiki/Beat_%28acoustics%29 http://en.wikipedia.org/wiki/Beat_%28acoustics%29