Objective characterization of perceptual dimensions underlying the sound reproduction of 37 single loudspeakers in a room

This study is focused on the relationships between perceptual and physical evaluations of the reproduction of timbre by loudspeakers in monophonic reproduction. A protocol compatible with both approaches was proposed by Lavandier et al.(2008) to evaluate a set of 12 loudspeakers. It consisted in recording the sound radiated by the loudspeakers in a room. The recorded sounds were submitted to listening tests under headphones where listeners were asked to judge their dissimilarity, highlighting the perceptual dimensions involved using a multidimensional scaling analysis. The recorded sounds were also submitted to signal analysis in order to propose an acoustical attribute describing each perceptual dimension. The present study further evaluated the reproduction of timbre by testing a set of 37 loudspeakers in a different room. Evaluating a larger set of loudspeakers led to constraints concerning the perceptual evaluation. Therefore, two perceptual tasks, free sorting and similarity picking with permutation of references, were compared. The perceptual results and the objective attributes of these experiments consolidate the two timbral dimensions revealed by Lavandier et al. (bass/treble balance, emergence of medium) and highlight a third dimension associated with a spatial sensation (feeling of space) despite a monophonic reproduction. An influence of the listening task was also observed, indicating that the free sorting paradigm might not be the most appropriate to evaluate dissimilarity.