Multidimensional microtiming in Samba music

Abstract

The connection of "groove" with low-level features in the audio signal has been mostly associated with temporal characteristics of fast metrical structures. However, the production and perception of rhythm in Afro-Brazilian contexts is often described as a result of multiple experience flows, which expands the description of rhythmical events to multiple features such as loudness, spectrum regions, metrical layers, movement and others. In this study, we analyzed how the microtiming of samba music interacts with an expanded set of musical descriptors. More specifically, we analyzed the interaction between fast timing structures with meter, intensity and spectral distribution within the auditory domain. The methodology for feature detection was supported by a psychoacoustically based auditory model, which provided the low-level descriptors for a database of 106 samba music excerpts. A cluster analysis technique was used to provide an overview of emergent microtiming models present in the features. The results confirm findings of previous studies in the field but introduce new systematic devices that may characterize microtiming in samba music. Systematic models of interactions between microtiming, amplitude, metrical structure and spectral distribution seem to be available in the structure of low-level auditory descriptors used in the methodology.