Audio Illusion: Shepard Tone

Someone in my ward introduced me to this odd, real life illusion. This is a video of what is called a Shepard Tone. From Wikipedia:

A Shepard tone, named after Roger Shepard, is a sound consisting of a superposition of sine waves separated by octaves. When played with the base pitch of the tone moving upwards or downwards, 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.

Take a listen to this clip from You Tube. You'll have to replay it a few times but it is interesting to notice that as you restart it, it sounds like it starts on a higher pitch than what it started on the first time. It's just one of those odd quirks that your brain gets fooled by:

1 comment:

Dave said...

Alright, that's the coolest thing ever.