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Journal Article

Audio Pitch Shifting Using the Constant-Q Transform

Authors: Schörkhuber, Christian; Klapuri, Anssi; Sontacchi, Alois

Journal of the Audio Engineering Society · Volume 61 · Issue 7/8 · pp. 562–572 · July 2013

Abstract

Pitch shifting of polyphonic music is usually performed by manipulating the time–frequency representation of the input signal such that frequency is scaled by a constant and time duration remains unchanged. A method for pitch shifting is proposed that exploits the logarithmic frequency-bin spacing of the Constant-Q Transform (CQT). Pitch-scaling of monophonic and dense polyphonic music signals is achieved by a simple linear translation of the CQT representation followed by a phase update stage. This approach provides a natural solution to the problems of transients because the CQT has good time resolution at high frequencies while interference between tonal components at low frequencies is reduced. Performing pitch shifting directly in the frequency domain allows the algorithm to process only parts of the signal while leaving other parts unchanged. Audio examples demonstrate the quality of the proposed algorithm for scaling factors up to an octave.

Details

Publication
Journal of the Audio Engineering Society
Volume
61
Issue
7/8
Pages
562–572
Publication date
July 6, 2013
Affiliation
Institute of Electronic Music and Acoustics, Graz, Austria; Ovelin, Helsinki (See document for exact affiliation information.)
Type
Journal Article