Wow

All recorded media are designed to play back at specific, stable rates of speed. If the record or playback speed fluctuates, random variations in the pitch of the program, called wow, will result. Wow is inherent in any mechanical transfer, though in an optimal transfer, it should be so minor as to be inaudible. Severe or noticeable wow can be caused by warped or damaged elements, faulty mechanical transports, or improper transfer procedures.

Wow is most easily recognized in sustained musical notes, which sound as if they are veering on and off pitch in an affected track. Few processes exist that can correct wow; Clarity™ Audio Restoration by Plangent Processes is one of the most successful.

This soundtrack suffers from extreme wow.

This clip contains a grossly exaggerated example of the type of pitch variation encountered in "wow."