Data enhancement is only the first level of auditory data representation. Utilization of the auditory channel to present unseen data is represented in this paper. The goal of these researchers was to use sound in a manner that "is intuitive enough and readily learnable enough to be effective as an additional sensory input to a mental model."

Rakowski, A. "Intonation Variants of Musical Intervals in Isolation and in Musical Contexts." Psych. Music 18 (1990): 60--72.

Rakowski presents experimental evidence to demonstrate that different musical intervals have different perceptual salience for musicians, some having more distant category boundaries and some more accurate recognition (strong and weak intervals). Further evidence is presented that musicians tune intervals to match perceptual categorizations. Three factors--acoustic (tuning to beats arising from its relationship with preceding note), psychological (perceptual) and aesthetic (accentuation of intervals)--all participate is this phenomenon.

Rasch, R. A., and R. Plomp. "The Perception of Musical Tones." In The Psychology of Music, edited by Diana Deutsch. New York: Academic Press, 1982.

Musicians' rank dyads in terms of their consonance and dissonance differently than naive subjects.

Richards, W. Natural Computation. Cambridge, MA: MIT Press, 1988.

This book includes seven chapters on sound interpretation including: representing acoustic information, models of binaural localization and separation, schematizing spectrograms, acoustics of the signing, recovering material properties from sound, perception of breaking and bouncing events, and perception of melodies.

Risset, J. C., and D. L. Wessel. "Exploration of Timbre by Analysis and Synthesis." In The Psychology of Music, edited by D. Deutsch. New York: Academic Press, 1982.

The authors describe analysis and synthesis as a technique for data reduction in computer music. Seminal work by founders of the field.

Roads, Curtis, and John Strawn, eds. Foundations of Computer Music. ISBN 0-262-68051-3. Cambridge, MA: MIT Press, 1985.

A survey of sound computation and other computer music issues.

Roads, Curtis, ed. The Music Machine. ISBN 0-262-18131-2. Cambridge, MA: MIT Press, 1989.

A collection of papers from Computer Music Journal.

Roederer, J. G. Introduction to the Physics and Psychophysics of Music. New York: Springer-Verlag, 1973.

A good introduction for the "intelligent layman."

Rothstein, Joseph. MIDI: A Comprehensive Introduction. Computer Music and Digital Audio Series, Vol. 7. John Strawn, Series Editor. Madison, WI: A-R Editions, 1992.

A thorough discussion of the basic principles of MIDI. Rothstein describes categories of MIDI instruments, accessories, and computer software, and tells how to get it all to work together.