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- Friberg, Anders
(författare)
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A Quantitative Rule System for Musical Performance
- 1995
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A rule system is described that translates an input score file to a musical performance. The rules model different principles of interpretation used by real musicians, such as phrasing, punctuation, harmonic and melodic structure, micro timing, accents, intonation, and final ritard. These rules have been applied primarily to Western classical music but also to contemporary music, folk music and jazz. The rules consider mainly melodic aspects, i. e., they look primarily at pitch and duration relations, disregarding repetitive rhythmic patterns. A complete description and discussion of each rule is presented. The effect of each rule applied to a music example is demonstrated on the CD-ROM. A complete implementation is found in the program Director Musices, also included on the CD-ROM.The smallest deviations that can be perceived in a musical performance, i. e., the JND, was measured in three experiments. In one experiment the JND for displacement of a single tone in an isochronous sequence was found to be 6 ms for short tones and 2.5% for tones longer than 250 ms. In two other experiments the JND for rule-generated deviations was measured. Rather similar values were found despite different musical situations, provided that the deviations were expressed in terms of the maximum span, MS. This is a measure of a parameter's maximum deviation from a deadpan performance in a specific music excerpt. The JND values obtained were typically 3-4 times higher than the corresponding JNDs previously observed in psychophysical experiments.Evaluation, i. e. the testing of the generality of the rules and the principles they reflect, has been carried out using four different methods: (1) listening tests with fixed quantities, (2) preference tests where each subject adjusted the rule quantity, (3) tracing of the rules in measured performances, and (4) matching of rule quantities to measured performances. The results confirmed the validity of many rules and suggested later realized modifications of others.Music is often described by means of motion words. The origin of such analogies was pursued in three experiments. The force envelope of the foot while walking or dancing was transferred to sound level envelopes of tones. Sequences of such tones, repeated at different tempi were perceived by expert listeners as possessing motion character, particularly when presented at the original walking tempo. Also, some of the character of the original walking or dancing could be mediated to the listeners by means of these tone sequences. These results suggest that the musical expressivity might be increased in rule-generated performances if rules are implemented which reflect locomotion patterns.
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| 4. |
- Friberg, Anders, et al.
(författare)
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Does music performance allude to locomotion? : A model of final ritardandi derived from measurements of stopping runners
- 1999
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Ingår i: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 105:3, s. 1469-1484
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Tidskriftsartikel (refereegranskat)abstract
- This investigation explores the common assumption that music and motion are closely related by comparing the stopping of running and the termination of a piece of music. Video recordings were made of professional dancers’ stopping from running under different deceleration conditions, and instant values of body velocity, step frequency, and step length were estimated. In decelerations that were highly rated for aesthetic quality by a panel of choreographers, the mean body velocity could be approximated by a square-root function of time, which is equivalent to a cubic-root function of position. This implies a linear relationship between kinetic energy and time, i.e., a constant braking power. The mean body velocity showed a striking similarity with the mean tempo pattern of final ritardandi in music performances. The constant braking power was used as the basis for a model describing both the changes of tempo in final ritardandi and the changes of velocity in runners’ decelerations. The translation of physical motion to musical tempo was realized by assuming that velocity and musical tempo are equivalent. Two parameters were added to the model to account for the variation observed in individual ritardandi and in individual decelerations: ~1! the parameter q controlling the curvature, q53 corresponding to the runners’ deceleration, and ~2! the parameter vend for the final velocity and tempo value, respectively. A listening experiment was carried out presenting music examples with final ritardandi according to the model with different q values or to an alternative function. Highest ratings were obtained for the model with q52 and q53. Out of three functions, the model produced the best fit to individual measured ritardandi as well as to individual decelerations. A function previously used for modeling phrase-related tempo variations ~interonset duration as a quadratic function of score position! produced the lowest ratings and the poorest fits to individual ritardandi. The results thus seem to substantiate the commonly assumed analogies between motion and music.
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- Friberg, Anders, et al.
(författare)
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Musical punctuation on the microlevel : Automatic identification and performance of small melodic units
- 1998
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Ingår i: Journal of New Music Research. - : Informa UK Limited. - 0929-8215 .- 1744-5027. ; 27:3, s. 271-292
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Tidskriftsartikel (refereegranskat)abstract
- In this investigation we use the term musical punctuation for the marking of melodic structure by commas inserted at the boundaries that separate small structural units. Two models are presented that automatically try to locate the positions of such commas. They both use the score as the input and operate with a short context of maximally five notes. The first model is based on a set of subrules. One group of subrules mark possible comma positions, each provided with a weight value. Another group alters or removes these weight values according to different conditions. The second model is an artificial neural network using a similar input as that used by the rule system. The commas proposed by either model are realized in terms of micropauses and of small lengthenings of interonset durations. The models are evaluated by using a set of 52 musical excerpts, which were marked with punctuations according to the preference of an expert performer.
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| 9. |
- Friberg, Anders, et al.
(författare)
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Performance Rules for Computer-Controlled Contemporary Keyboard Music
- 1991
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Ingår i: Computer music journal. - 0148-9267 .- 1531-5169. ; 15:2, s. 49-55
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Tidskriftsartikel (refereegranskat)abstract
- A computer program for synthesis of music performance, originally developed for traditional tonal music by means of an analysis-by-synthesis strategy, is applied to contemporary piano music as well as to various computer-generated random music. The program consists of rules that manipulate the durations and sound levels of the tones in a contextdependent way. When applying the rules to this music, the concept harmonic charge, which has been found useful for generating crescendi and diminuendi in performance of traditional tonal music for example, is replaced by chromatic charge. The music is performed on a Casio sampler controlled by a Macintosh II microcomputer. A listening panel of five experts on contemporary piano music or electroacoustic music clearly preferred performances processed by the performance program to "deadpan" performances mechanically replicating the durations and sound levels nominally written in the music score.
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- Friberg, Anders, et al.
(författare)
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Recent musical performance research at KTH
- 1994
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Ingår i: Proceedings of the Aarhus symposium on Generative grammars for music performance 1994. ; , s. 7-12
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Konferensbidrag (refereegranskat)
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