This project follows up on Luk Vaes’ doctoral work with regards to extended piano techniques. In contemporary music, clusters (dense aggregates of adjacent pitches) have become a common part of the musical language. Yet, our understanding of how clusters are perceived does not match its popularity in compositional practice. The few existing cluster theories are contradictory to each other as well as to the cluster’s history in scores; empirical data on the cluster's aural perception are almost non-existing.
Considering a cluster to be a psycho-physiological phenomenon of which the individual constituents are losing perceptibility in favor of its contour, a double experiment was set up to study the aural perception of aggregates with varying degrees of density within a fixed contour. The primary interest was vested in detecting quantity (number of tones), quality (identity of tones), cohesion (gaps in the accumulation) and contour (size of the interval).