Project Proposal

As a result of such studies, the Wigner Distribution (WD), originally developed for joint distribution in Quantum Mechanics, has been applied to signal analysis and its superiority has been established for accurate time-frequency representation. In the context of the representation of musical timbres, the WD allows accurate analysis of both temporal and spectral details, and thereby facilitates synthetic processing of both transient and steady-state aspects of musical tones. This in turn opens up previously unexplored vistas in timbre space in that timbre manipulation is not confined to spectral processing. With an ability to see the full detail of temporal and spectral composition of musical timbres comes the desire to manipulate these same details for the purpose of creative, musical expression.

One approach to the exploration of timbre space is based on the possibilities inherent in morphing between two choosen timbres.The concept of visual morphing is familiar to many from special effects processing in cinema. A good example is where we are shown a young face gradually and smoothly age as it moves from youth to old age. This is achieved by using two frames - one young and the other old - and manipulating various perceptually significant parameters so that the presented face appears to move from the youthful starting frame to the aged finishing frame. An exactly analogous process may be applied to musical timbres. For example, we may choose a violin starting timbre and a flute finishing timbre and manipulate various important (spectral and temporal) features so that we can move smoothly between them. By so doing we open up new parts of timbre space which nevertheless are not entirely unknown to us in that we would at least be opperating between the known boundaries of 'violin' and 'flute', or whatever other timbres we had choosen at the outset.

Thus Morphing would provide the composer with access to a much richer timbre palette than here before, in that previously inexplored regions of timbre space could be made available for creative manipulation. By basing such morphing tools on WDs of musical tones, rather than Spectrograms, representational distortions would be minimized and detailed spectral and temporal features of real instrument tones would be made much clearer for the purposes of computational analysis and synthesis.

With regard to research, it is proposed to develop a computer-based tool which would facilitate timbre morphing and provide the composer with a vastly expanded timbre palette. The work would involve a number of stages:

As with the case of the development of many application tools, the cross-disciplinary nature of the proposed research requires a significant input from both the technological and the musical domains. To be truely useful as a tool for composition, it is essential that the researcher be well versed in musical composition and have appreciation of those features which would be important from the perspective of the musician. Obviously the reverse scenario also holds true in that the development of the type of tools which might be desired by the composer for timbre exploration requires considerable technical expertise. It is believed, therefore that this project is an ideal vehicle for interaction between the DIT College of Music and TCD Department of Electronic and Electrical Engineering, as both parties have a strong interest in aspects of the other's domain of activity. Research in audio and musical acoustics has been ongoing in TCD Department of Electronic and Electrical Engineering for over a decade, while DIT College of Music have an emerging interest in the exploration of technological aids for composition and performance. Given such, it is hoped that significant advantages will accrue to both parties through the involvment and interaction which the proposed project will necessitate.
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