What/when causal expectation modelling applied to percussive audio

A causal system for representing a musical stream and generating further expected events is presented. Starting from an auditory front‐end which extracts low‐level (e.g., spectral shape, mel frequency cepstral coefficients) and midlevel features such as onsets and beats, an unsupervised categorisation process builds and maintains a set of symbols aimed at representing musical stream events using both timbre and time descriptions. The time events are represented using inter‐onset intervals relative to the beats. These symbols are then processed by an expectation module based on predictive partial match, a multiscale technique derived from N‐grams. The system capacity to generate an expectation that matches its transcription is evaluated using drum recordings from the ENST‐drums database. We show that the MFCC‐based representation leads to a more compact set of symbols and a better match between transcription and expectation. Also, we suggest that the system is sensitive to exposure and illustrate some prop...