The Shepard Tone is an audio illusion formed by overlaying separate tones separated by octaves that each rise/fall (depending on the nature of the Shepard Tone in question) and repeat independently of one another. As a result, in this case the sound seems to continuously get higher but never really does.
(Would appreciate it if “““companies“““ like ’DeepMiningCorpAssoc’ stopped putting in false copyright claims, you’re ruining it for everyone else).
Source of sound graph: :
All sounds and images in this video are in the public domain and not copyrighted, feel free to use it!
Shepard tone sound was downloaded from Soundcloud (sound not copyrighted), (Thanks to a guy in the comments).