an organum is a form of early polyphony based on an existing plainsong.
a polyphony is the style of simultaneously combining a number of parts, each forming an individual melody and harmonizing with each other.
a gregorian chant is church music sung as a single vocal line in free rhythm and a restricted scale (plainsong), in a style developed for the medieval Latin liturgy.
Ability to consciously focus attention upon environmental. and musical sound. Sonic awareness is ideally characterized. by a continual alertness to sound and an inclination to be. always listening.
