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Published 1985 | public
Book Section - Chapter

A VLSI Approach to Sound Synthesis


We present a VLSI approach to the generation of musical sounds. This approach allows the generation of very rich musical sounds using models that are easy to control and have parameters corresponding to physical attributes of musical instruments. Past efforts in musical sound generation have been plagued with several problems. The computational bandwidth that is needed to compute musical sounds is enormous, and it is hopeless to compute sounds in real time on a conventional general purpose computer. An even larger problem with previous efforts is the massive bandwidth needed for control and update of parameters. Sounds that come from physical sources are naturally represented by differential equations in time. Since there is a straight-forward correspondence between differential equations and finite difference equations, we can model musical instruments as simultaneous finite difference equations. Musical sounds can be produced by solving, in real time, the difference equations that model instruments. A natural architecture for solving finite difference equations is one with an interconnection matrix between processors that can be reconfigured or "programmed". A realization of a new instrument involves reconfiguring the connection matrix between the processing elements along with configuring connections to the outside world both for control and updates of parameters. For our basic unit of computation we have chosen a unit we call a UPE (Universal Processing Element) - it computes the function: A + BM + (1 - M)D We have implemented in nMOS technology a prototype systems of UPEs and have been successful in implementing some simple musical instruments on the system of UPEs.

Additional Information

© 1985 Computer Music Association. Many people have contributed in unique ways to the Music Project at Caltech. Tzu-Mu Lin (at the time, a Ph.D. candidate at Caltech) did much of the basic work on the UPE design. Lounette Dyer (graduate student) has built a highlevel front end to the hardware and brings a musical sensitivity to the project. Hsui-Lin Liu (postdoctorate, now at Schlumberger-Research) comes from a background in seismology and acoustics and did work on physical modelling of musical instruments. Dick Lyon (Fairchild Research Lab), whose multipliers the UPE is based, has provided countless ideas and is always an inspiration. Greg Bala (Undergraduate, now at IBM) has worked with the project from its beginning and has contributed application software. Ron Nelson (composer and Professor of Music at Brown University) has worked with the project to make our instrument models more realistic and useable. David Feinstein (graduate student) has done soine exquisite mathamatics which helped us develop instrument models. Vibeke Sorenson (instructor at Art Center College of Design) was the first user of the sound synthesis hardware. Special thanks are due Telle Whitney (graduate student) for her critiques.and many discussions. We would also like to thank Ron Ayres (USC/Information Sciences Institute) whose circuit layout programs were used to generate the custom chips. The circuit boards that hold the custom chips were designed and built by Brian Horn. Jim Campbell and Alan Blanchard have contributed hardware support. This work was supported by the System Development Foundation.

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August 19, 2023
March 5, 2024