The Shepard Tone creates the illusion of continuously swelling sound, which can build tension or suspense. Find out how it works in this breakdown…The Shepard Tone. If you’ve never heard of this term, I can almost guarantee you’ve heard the tone itself. The term refers to an auditory illusion of a sound that continually ascends (or descends) in pitch.
The tone is a sound that comprises multiple sine waves separated by an octave and layered on top of each other. In essence, there is a high-pitched tone, a middle-pitched tone, and a low-pitched tone that all rise in pitch until they loop back to the start. By the end of the track, the highest-pitched tone has become quiet, the middle-pitched tone stays loud, and the low-pitched tone has become louder. Because you can always hear two tones rising in pitch, your brain skips the loop and believes the tone is infinitely ascending. Read the article at Premium Beat.
A Shepard tone, named after Roger Shepard, is a sound consisting of a superposition of sine waves separated by octaves. When played with the bass pitch of the tone moving upward or downward, it is referred to as the Shepard scale. This creates the auditory illusion of a tone that continually ascends or descends in pitch, yet which ultimately seems to get no higher or lower. Read more at Wikipedia.