Variations in air pressure against the eardrum. The subsequent physical and neurological processing and interpretation, give rise to the experience called sound. Most sound that people recognize as "musical" is dominated by periodic or regular vibrations rather than non-periodic ones (called a definite pitch and we refer to the transmission mechanism as a "sound wave". In a very simple case, the sound of a sine wave, which is considered the most basic model of a sound waveform, causes the air pressure to increase and decrease in a regular fashion, and is heard as a very "pure" tone. Pure t…
