The Fast Fourier Transform (FFT ) is a powerful general-purpose algorithm widely used in signal analysis. FFI’s are useful when the spectral information of a signal is needed, such as in pitch tracking or vocoding algorithms. The FFT can be combined with the Inverse Fast Fourier Transform (IFFT) in order to resynthesize signals based on its analyses. This application of the FFT/IFFT is of particular interest in electro-acoustic music because it allows for a high degree of control of a given signal’s spectral information (an important aspect of timbre) allowing for flexible, and efficient implementation of signal processing algorithms.
This paper presents real-time musical applications using the IRCAM Signal Processing Workstation (ISPW) [Lindemann, Starkier, and Dechelle 1991] which makes use of FFT/IFFT based resynthesis for timbral transformation in a compositional context. Taking a pragmatic approach, the authors have developed a user interface in the Max programming environment [Puckette, 1988] for the prototyping and development of signal processing applications intended for use by musicians. Techniques for filtering, cross-synthesis, noise reduction, and dynamic spectral shaping have been explored, as well as control structures derived from real-time signal analyses via pitch-tracking and envelope following [Lippe & Puckette, 1881]. These real-time musical applications offer composers an intuitive approach to timbral transformation in electro-acoustic music, and new possibilities in the domain of live signal processing that promise to be of general interest to musicians.
- Zack Settel & Cort Lippe, IRCAM, Paris, France
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