The least-squares invertible constant-Q spectrogram and its application to phase vocoding.
This paper discusses the development of a constant-Q spectrogram representation that is invertible in a least-squares sense. A good quality inverse is possible because this modified transform method, unlike the usual sliding window constant-Q spectrogram, does not discard data samples when performing the variable length discrete Fourier transforms on the signal. The development of a phase vocoder application using this modified technique is also discussed. It is shown that a phase vocoder constructed using the least-squares invertible constant-Q spectrogram (LSICQS) is not a trivial extension of the regular FFT-based phase vocoder algorithm and some of the mathematical subtleties related to phase reassignment are addressed.
Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, USA. ingle@wisc.edu
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Ingle
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Sethares
D000162:Acoustics; D000465:Algorithms; D003198:Computer Simulation; D005583:Fourier Analysis; D016018:Least-Squares Analysis; D015233:Models, Statistical; D009146:Music; D012815:Signal Processing, Computer-Assisted; D013016:Sound; D013018:Sound Spectrography; D013997:Time Factors