Expressive Performance
Performance strategies and performance rules
Timmers, R., Ashley, R, Desain, P, and Heijink, H. (2000). The influence of musical context on tempo rubato. Journal of New Music Research 29 (2), 131-158.
Different pieces of music offer different expressive possibilities. Even a single piece of music offers the possibility to be treated in several expressive ways (see "Repp (1998)"). How much of this variety of possible interpretations is exhibited in actual performances of the music? Do pianists make use of the different parameters of the piece to shape their performance? Do variety in performances and variety in musical parameters relate to each other? Previous studies stress the relation between timing variations and musical structure (see "Clarke (1985)"), but provide no clear answer to the freedom that is allowed within this regularity, especially when multiple structural descriptions play a role simultaneously.
In an experiment, the melody of Variations on an Original Theme (Op. 21, No. 1) by Brahms, is set in different musical contexts derived from the Theme. Three pianists are asked to perform the melody in the different settings from a score. They repeat each performance several times. The settings are 1) the melody without bar-lines, 2) the melody with bar-lines, 3) the counter-melody, 4) the melody with the counter-melody, 5) the melody with block chords, 6) the Theme. The Theme contains all material of previous settings (the melody, counter-melody and block chords). The settings are presented in a fixed order and the pianists do not know the pieces before hand.
Analysis of the recorded performances shows that pianists change the onset timing of the melody with respect to the musical context in which the melody is presented. Aspects of the context are imbedded in the timing pattern in different ways; for example, the addition of chords often causes a lengthening of the melody notes with chords, and the addition of a counter-melody constrains the lengthening of a melodic ornament. The melody proves to be the primary expressive source, while chords and a counter melody are good second ones. Both the variety in timing patterns and the extent of tempo rubato appear to increase with increasing complex conditions.
Timmers, R. (2003). On the contextual appropriateness of expression. Music Perception, 20, 225-240.
The aim of this study was to show that the quality of an expressive interpretation depends on expressive context. The main hypothesis was that expression is evaluated in relation to preceding expressive variations. Two experiments and a model tested this hypothesis. In the first experiment, 39 listeners rated the quality of the performance of the continuation (second half of the musical stimulus) given the performance of the initiation (first half of the musical stimulus). The results showed a significant effect of continuation on the quality judgements and a significant interaction between continuation and initiation. This interaction was seen as the first confirmation of the hypothesis. In the second experiment, 20 participants rated the quality of the six performances of the initiation and of the continuation separately. The results of this experiment were unable to explain the quality judgements of experiment 1. The low agreement between the judgements was taken as a second confirmation that contextual considerations can overrule general aesthetic preference. A regression model was proposed that predicts the quality rating of experiment 1 from the similarity in rubato extent, key velocity pattern, average articulation, grace note duration and average asynchrony between the two segments. This model was better able to explain the quality judgements of the continuation, providing final confirmation that the quality of the second half was a function of its agreement with the first half.
Timing of ornaments
Timmers, R., Ashley, R., Desain, P., Honing, H., & Windsor, L. W. (2002). Timing of ornaments in the theme from Beethoven´s Paisiello Variations: Empirical Data and a Model. Music Perception, 20, 3-33.
Musicians have to make many interpretive decisions when performing a piece. For example, the grace note, a one-note musical ornament, has no precise duration written in the score; it has to steal its duration from either the preceding or following melody notes. There were several empirical questions this study sought to answer: What duration are grace notes given? Does this vary depending upon musical context or individual preferences? And, are their durations taken from the preceding or subsequent melody note, or is time added? In an experiment, 16 professional pianists performed 3 musical fragments (from a Beethoven Theme) `with´ and `without´ grace notes in 7 different tempi. The timing of the grace notes was found not to be proportional to changes in global tempo for most, but not all performers, which replicates earlier studies. In the majority of cases increases in bar duration were matched by relative increases in grace note duration that were smaller than predicted by a proportional tempo model, with a minority of subjects performing grace notes with fixed duration over tempo. In most cases, grace note duration was `stolen´ from the preceding melody note, with a small contribution from the following (main) note, and with minimal disturbance to local tempo. Conversely, where grace notes were played as appoggiatura, the main source of their duration was the main note. The type of grace note performed depended both on its musical context and on individual differences between performers. A model of grace note duration is proposed to account for these results.
Windsor, L. W., Desain, P., Aarts, R., Heijink, H., Timmers, R. (2001). The timing of grace notes in skilled musical performance at different tempi: a case study. Psychology of Music, 29, 149-169.
An experiment is reported which investigates the relationship between musical structure, predictions from the performance practice literature, and the timing of 11 grace notes in 45 performances of a short Beethoven piano piece at a range of tempi. These performances were recorded and analyzed so as to extract timing measurements, and the pianist was interviewed to gain insights into his conscious performing strategies. Significant differences in the relative length of different grace notes were found: the two grace notes with a large descending pitch interval were played significantly longer than the others. Additionally, the grace notes were timed such that they did not 'take time' from the note they are nominally attached to, but from the preceding time interval. Close attention to the qualitative data provided by the pianist reveals that the relative timing of the grace notes is best explained by his efforts to mimic the motor constraints of vocalists and string players, and by his tacit avoidance of dissonant vertical relationships between melody and accompaniment. Both of these interpretative decisions are in line with an explicit decision to attempt to play the piece in a 'song-like' manner. Lastly, the data provided evidence against the notion that changes in overall tempo leave the relative proportion of adjacent events invariant. Grace notes with a longer mean duration tended to deviate significantly from proportional duration, whilst shorter grace notes were roughly invariant over tempo. In summary, the results suggest that, in addition to the performer's grasp of musical structure, both overall tempo and subtle communicative issues play important and measurable roles in determining the timing of musical events.
See also expression and perception of emotion in performance (under Musical meaning and emotion).