Two short pieces of freely improvised music by the same performer were recorded in microstructural detail by the use of a specially constructed automatic transcription apparatus. The apparatus consists of a modified DX7 synthesizer and 2650 microprocessor which interfaces with other computers for data processing. The resultant music is transcribed into a modified form of traditional notation and subjected to both micro- and macrostructural analysis. Microanalysis includes the areas of timing (interonset and duration distributions, displacement, chordal spreads, etc.), dynamics ( key velocity, quantization, chordal patterns, etc.), and legatoness (relative, absolute, pedaling). Macroanalysis uses the full panoply of devices from traditional music theory (tonal procedures, rhythmic and motivic design, pitch class sets, etc.). Correlations between microstructural parameters, and with macrostructure, were found to be highly significant in Improvisation A, which had a supplied external pulse, but largely absent in Improvisation B, which had no such pulse. Where pulse was present, rhythmic design was found to be based largely on pulse subdivision and shifting. Some performance effects (e.g., chordal spreads) operated over a time scale of 10 msec or less. Others (e.g., synchronization to an external pulse) showed less resolution. Differences in the distribution patterns of interonset times, durations, and legatoness suggest three independent underlying temporal mechanisms that may sometimes link together in coordination with macrostructure. Quantization ("categorical production") of some variables (interonset times, key velocities) was clearly established. The results were also interpreted in relation to an earlier model of improvisation (Pressing, 1987).

References

References
Gabrielsson, A. Performance of rhythm patterns. Scandinavian Journal of Psychology, 1974, 15, 63-72.
Gabrielsson, A. Perception and performance of musical rhythm. In M. Clynes (Ed.), Music, mind, and brain. The neuropsychology of music. New York: Plenum Press, 1982.
Hood, M. The ethnomusicologist. Kent, OH: Kent State University Press, 1982.
Jones, A. M. Studies in African music. London: Oxford University Press, 1959.
Lamb, M. R. Andre Tchaikovsky meets the computer: a concert pianist's impromptu en- counter with a musicianship teaching aid. International Journal of Man- Machine Stud- ies, 1978, 10,593-602.
MacKenzie, C. L., VanEerd, D. L., Graham, E. D., Huron, D. B., & Wills, B. L. The effect of tonal structure on rhythm in piano performance. Music Perception, 1986, 4, 215-226.
Michon, J. A. Programs and 'programs' for sequential patterns in motor behaviour. Brain Research, 1974, 71,413-424.
Povel, D. J. Temporal structure of performed music. Acta Psychologica, 1977, 41, 309- 320.
Pressing, J. Cognitive processes in improvisation. In W. R. Crozier and A. J. Chapman (Eds.), Cognitive processes in the perception of art. Amsterdam: North Holland, 1984, pp. 345-363.
Pressing, J. Improvisation: methods and models. In J. Sloboda (Ed.), Generative processes in music. London: Oxford University Press, 1987, pp. 129-176.
Rasch, R. A. Synchronization in performed ensemble music. Acustica, 1979, 43, 121-131.
Seashore, C. E. Psychology of music. New York: McGraw-Hill, 1938.
Shaffer, L. H. Analysing piano performance: a study of concert pianists. In G. E. Stelmach Oc J. Requin (Eds.), Tutorials in motor behaviour. Amsterdam: North Holland, 1980.
Shaffer, L. H. Performances of Chopin, Bach, and Bartok: Studies in motor programming. Cognitive Psychology, 1981, 13,326-376.
Shaffer, L. H. Timing in musical performance. Annals of the New York Academy of Science, 1984a, 423, 420-428.
Shaffer, L. H. Timing in solo and duet performances. Quarterly Journal of Experimental Psychology, 1984b, 36A, 577-595.
Sloboda, J. A. The communication of musical metre in piano performance. Quarterly Jour- nal of Experimental Psychology, 1983, 35 A, 377-396.
Small, A. M., 6c Campbell, R. A. Temporal differential sensitivity for auditory stimuli. American Journal of Psychology, 1962, 75,401-410.
Tucker, W. H., Bates, R. H., Frykberg, S. D., Howarth, R. J., Kennedy, W. K., Lamb, M. R., & Vaughan, R. G. An interactive aid for musicians. International Journal of Man- Machine Studies, 1977, 9, 635-651.
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