Comparative Melodic Analysis of A Cappella Flamenco Cantes

Background in ethnomusicology and music analysis. A cappella singing styles (called cantes in the flamenco jargon) are among the most fundamental song styles within the flamenco repertoire. Until very recently, flamenco singers have been only using oral transmission to learn them. Because of this form of diffusion, melody has become one of the main musical facets to be listened to, remembered, elaborated and spread in flamenco singing styles. Moreover, melody has helped flamenco enthusiasts to remember and identify variants of a particular style or genre. A frequent discussion and unanswered question among flamenco scholars is how to quantify the similarity between two melodies, and how to use this similarity measure to differentiate different styles and variants among performers, and to study the roots and evolution of flamenco styles.

Background in computing, mathematics and statistics. State of the art techniques in melodic analysis of audio allow us to obtain different representation levels of a music recording (Gómez et alt. 2003). There are different representation levels for melody. Energy (intensity) and fundamental frequency (pitch) curves are the main low-level melodic features. In a higher structural level, note duration and pitch provide a symbolic representation, which can be the input to higher-level analyses. Finally, deviations of the analyzed recording with respect to the obtained score are related to expressivity. There have been some attempts to apply these techniques to the analysis of flamenco music (Donnier 1997, Gómez and Bonada 2008). There also a corpus of research on how to measure similarity between melodies using computational models, which are usually inspired in methods for string comparison (Crawford et alt. 1998, Mongeau and Sankoff 1990).

Aims. After some previous studies on rhythmic similarity of flamenco styles (Díaz-Bañez et alt. 2004), the aim of this work is to compare different approaches of melodic and tonal analysis of flamenco a capella singing styles. The ultimate goal is to perform a multidisciplinary analysis that will provide us with tools to compare different versions of the same style, and, as a consequence, to clarify the roots of styles and their evolution. We contrast historical knowledge, we carry out manual melodic and tonal analysis assisted with automatic melodic description tools. In order to achieve this goal, it is also necessary to gather a representative musical corpus, a significantly difficult task due to the variety of media (mostly vinyl and magnetic tapes) and poor quality of existing flamenco recordings.

Main contribution. One of the main contributions of this work is to gather a representative music collection for this study. The corpus was found on very diverse media (mostly vinyl and magnetic tapes), and comprises recording from the 40’s up to day. We have considered a music collection of songs without instrumentation or in some cases with some percussion, known in flamenco music as cantes a palo seco . This corpus is composed of two main styles, namely: martinetes and tonás . In total, there are 135 monophonic voice pieces covering the most representative flamenco singers. Musicological and historical criteria were followed when selecting the pieces.

As a second step, we have performed different analysis of this music collection. From a musical and computational perspective, we first define a melodic representation capable of coping with the relevant subtleties of this kind of style, characterized by ornamentations. This melodic representation is automatically computed from the selected phrases (Gómez and Bonada 2008). Critical issues have risen regarding the location of the main notes of the melody, the idiosyncratic use of vibrato and the presence of non-equal-tempered intervals. After that, some similarity measures between each pair of pieces have been computed, such as the edit distance (Gascuel 1997), in order to obtain a similarity matrix for the studied corpus. We compared the obtained similarity matrix with a set of manual annotations produced by flamenco experts; those manual annotations included perceptual melodic contour, tonal analysis as well as historical data based on previous well-established facts and tenets about the analyzed corpus. The different analyses are presented in the paper, and we will listen to some examples of the analyzed pieces in the conference presentation.

Conclusions. Melody is one of the most important aspects to consider when analyzing a cappella flamenco singing styles. Automatic melodic description tools have proven useful to the analysis of flamenco voices, notwithstanding the traditional techniques of music analysis. These automatic tools allow us obtaining quantitative measures that can complement historical data on the roots and the evolution of oral transmission styles.