Time stretching
Time stretching is a term used in audio technology and describes the changing of the playback speed of audio material without changing the pitch.
Is the opposite of time-stretching the pitch change (fachsprachlich English pitch shifting ), only the pitch, but not the playback speed is changed when. The mathematical basis for both methods is often the fast Fourier transform .
Time stretching and pitch changes can only sound “realistic” within certain limits. Values of around 15 to 20% deviation from the original material produce audible noise ( grain or reverberation artifacts ) that audibly alienate the original. but can be partially used as an effect.
Newer methods now allow an improved quality that can be maintained over a larger area.
literature
- Roland Enders: The home recording manual. 3rd edition, Carstensen Verlag, Munich, 2003, ISBN 3-910098-25-8
- Thomas Görne: Sound engineering. 1st edition, Carl Hanser Verlag, Leipzig, 2006, ISBN 3-446-40198-9