(1) THE FOLLOWING TEXT IS A REWRITE OF THE ORIGINAL ARTICLE ENTITLED "LOW
DIMENSIONAL CONTROL OF MUSICAL TIMBRE". IT IS AN IMPROVED VERSION AND
COVERS THE SAME MATERIAL AS THE ORIGINAL TEXT.
This text was published in volume 3 Number 2 of the Computer Music Journal in June of 1979. The Computer Music
Journal is now published by the M.I.T. Press, Cambridge, Massachusetts.
(2) Research on musical timbre typically seeks representations of the perceptual structure inherent in a set of sounds that
have implications for expressive control over the sounds in composition and performance. With digital analysis-based
sound synthesis and with experiments on tone quality perception, we can obtain representations of sounds that
suggest ways to provide low-dimensional control over their perceptually important properties.
In this paper, we will describe a system for taking subjective measures of perceptual contrast between sound objects
and using this data as input to some computer programs. The computer programs use multidimensional scaling
algorithms to generate geometric representations from the input data. In the timbral spaces that result from the scaling
programs, the various tones can be represented as points and a good statistical relationship can be sought between the
distances in the space and the contrast judgments between the corresponding tones. The spatial representation is given
a psychoacoustical interpretation by relating its dimensions to the acoustical properties of the tones. Controls are then
applied directly to these properties in synthesis. The control schemes to be described are for additive synthesis and
allow for the manipulation of the evolving spectral energy distribution and various temporal features of the tones.
Tests of the control schemes have been carried out in musical contexts . * Particular emphasis will be given here to
the construction of melodic lines in which the timbre is manipulated on a note-to-note basis. Implications for the
design of human control interfaces and of software for real-time digital sound synthesizers will be discussed.