Siddiq, Saleh; Reuter, Christoph; Czedik-Eysenberg, Isabella and Knauf, DenisProceedings of the Third Vienna Talk on Music Acoustics (2015), pp. 237–240
Background: The perceptual relations of musical timbres are difficult to assess. The so called timbre spaces (TS) are a concept to depict timbre dissimilarities as spatial distances in a euclidean space. Since the 1970s, the TS concept, as intuitively accessible as it is, gained popularity within the scientific community and has been generally accepted. A recent comparison of several TS revealed a lack of consistency among TS studies (Siddiq et al. 2014). It's most likely caused by the from study to study vastly different stimuli-sets. Thus far, instruments were reduced to a single tone, compared at the same pitch, and only (re-)synthesized sounds were used. Research question: These findings raise the question whether an empirical meta TS would rather comply with the results of the original TS or confirm the inconsistency. Methods: Based on the original stimuli used by Grey (1975), Krumhansl (1989), McAdams et al. (1995), and additional natural instrument sounds out of the Vienna Symphonic Library (VSL), a hearing experiment was performed. The obtained dissimilarity matrix was, by means of a multidimensional scaling (MDS), graphed into a 3D scatter plot and eventually structured through a hierarchical clustering. Results: The inconsistency is pretty much confirmed. Instead of an anticipated instrument clustering (e.g. all trumpets roughly located in the same region), the meta TS yields a clear clustering of stimuli-sets. Apparently, there is a greater timbral resemblance among the different instrument sounds from the same stimuli-set than among the sounds of the same instrument across the different stimuli-sets. Hence, these timbral differences between the stimuli-sets seem to prevail as primary features of timbre discrimination which in turn significantly impairs the comparability and thus the generality of TS studies.