Cort Lippe

Real-time timbral transformation: FFT-based resynthesis

This paper presents real-time musical applications using the IRCAM Signal Processing Workstation which make use of FFT/IFFT-based resynthesis for timbral transformation in a compositional context. An intuitive and straightforward user interface, intended for use by musicians, has been developed by the authors in the Max programming environment. Techniques for filtering, cross-synthesis, noise reduction, and dynamic spectral shaping are presented along with control structures that allow for both fine timbral modification and control of complex sound transformations using few parameters.

Real-Time Interactive Digital Signal Processing: A View of Computer Music

when i was approached to write a short article for the twentieth anniversary of the Computer Music Journal, i re-read volume 15, number 4, a CMJ issue dedicated to “Dream Machines for Computer Music”...it is a fascinating issue, published five years ago, yet it does not in the least seem dated today...if technology is advancing as rapidly as the media would have us believe, then should not some of our dreams be a reality?...men went to the moon almost 30 years ago (nevermind the reasons) yet what has happened to all our fantasies of space exploration since then?...is the computer music field moving forward as it should, or are we as dependent on market forces as the space “race” was dependent on political forces?...

Real-time musical applications using frequency domain signal processing

This paper presents real-time musical applications using the IRCAM signal processing workstation which make use of FFT/IFFT-based resynthesis for timbral transformation in a musical context. An intuitive and straightforward user interface, intended for use by musicians, has been developed by the authors in the Max programming environment. Techniques for high quality time-stretching, filtering, cross-synthesis, dynamic range processing, and spectrum shaping are presented along with dynamic control structures that allow for both fine timbral modification and control of complex sound transformations using few parameters.

Low-dimensional audio-rate control of FFT-based processing

While the use of the fast Fourier transform (FFT) for signal processing in music applications has been widespread, applications in real-time systems for dynamic spectral transformation have been quite limited. The limitations have been largely due to the amount of computation required for the operations. With faster machines, and with suitable implementation for frequency-domain processing, real-time dynamic control of high-quality spectral processing can be accomplished with great efficiency and a simple approach. This paper describe some previous work in dynamic real-time control of frequency-domain-based signal processing. Since the implementation of the FFT/IFFT is central to the approach and methods discussed, the authors provide a description of this implementation, as well as of the development environment used in their work.

Real-time computer music at IRCAM

Real-time applications have always been an important dimension of and integral to the basic philosophy of computer music at IRCAM. At present, there is a great deal of activity in this domain in the areas of hardware, software, and musical production. A project is underway to develop a new real-time workstation to replace the 4X. The workstation group hopes to develop a powerful portable system which will be easy for musicians to use on an intuitive level. Probably the most important question concerning real-time computer music is the interface between musician and machine. Some of the most interesting software to be written at IRCAM, Miller Puckettes Patcher, is a real-time object-oriented, graphics based, musical programming language in which objects send and receive messages. IRCAM supports approximately a dozen musical productions each year. Of these, about 60% involve the computer in real-time concert situations. A list of all works created at IRCAM using electronics in real-time is included.