Performing proportion: crux awareness in Scarlatti interpretation

After an initial study (Harper, 2007) revealed a high crux-phi incidence in selected Scarlatti sonatas, Harper and Henriques, (2008)) examined ten recorded performances of K. 380 from the perspective of interpretative treatment of the crux – “the point in each half at which the thematic material, which is stated in parallel fashion at the ends of both halves, establishes the closing tonality”. The current study, based on six commercially available recordings of K. 159, and two unedited recordings by performers familiar with the ‘crux’ concept, examines evidence for a proportional sense of crux by composer, and a response to it by performers. A Scarlatti Sonata was chosen on grounds of its structural proportions, and acessibility of both commercial and unedited recordings on modern piano and historical keyboard instruments. Using audio digital editors, time readings of all performances were taken at several key moments. Equalized measurements with Audacity 1.3.3 & Peak 5 were taken and compared using Pogorelich’s interpretation as the median. Conclusions were drawn about the proportional sense of crux as reflected by performers. Although GS proportion is not present in K. 159, a mirrored symmetrical proportion is found: the crux occurs three measures before phi in the first half and three measures after phi in the second half. Performances in the two samples (commercial recordings/ live unedited recordings) ranged from MM 110 to MM 128. In comparing the length-ratios of the recordings that were time-modified to the chosen model (Pogerelich MM=112), it was found that performers tended to modify their overall tempo at the key points identified in the analysis. The underlying temporal framework. Conclusions: When repeats are played, the length of the A section corresponds to the occurrence of the crux in the B section (52 measures), indicating that the inclusion of repeats might be regarded as integral to the structure. Regardless of different types of recording (edited/unedited) and choice of instruments (piano/harpsichord), two performances of the same duration occurred in this sample. We infer that there is a proportional sense of crux by composer and by performers, evident in both foreground (surface) and background (structural) tempi.