Logic Pro 9 User Manual: Using the Sample Editor’s “Time and Pitch Machine”

Using the Sample Editor’s “Time and Pitch Machine”
You can use the “Time and Pitch Machine” to radically alter the time structure of audio files, including time compression or expansion, and pitch transposition. When changing the pitch, you can also correct any alteration of the formants—the vocal characteristics of the pitch-shifted audio. Pitch shifting without formant correction causes a phenomenon commonly known as the Mickey Mouse effect.

In the “Time and Pitch Machine,” time and pitch functions can be carried out together, or can be performed independently of one another.