Time Compression/Expansion

A process where a soundfile of a given length is electronically sped up or slowed down so it will play in a shorter or longer period of time. When speaking of time compression or expansion it is generally assumed that the pitch of the material is not changed, so this isn’t as simple as just speeding up or slowing down the playback device. This type of process requires that the material’s playback speed be adjusted and then some type of pitch correction applied to return its pitch to normal. These techniques have been fairly common for a number of years, particularly in commercial studios where it is common to have a 32 second (for example) commercial that must run in a 30 second slot of time.