Listening test methods for perceptual assessment of structural uncertainty

Because of structural uncertainty, an industrial product can exhibit a large variability in its vibratory and acoustical behavior. Many studies have investigated the variation in noise and vibration between structures with nominally identical design. However, the variation of sound perception caused by structural uncertainty has not yet been studied. The aim of this study was to investigate how to assess the perceptual consequences of that physical variability. A mechanical model system, on which structural uncertainty could be simulated, was set up for sound synthesis. The sounds “emitted” by this product were then assessed by a group of listeners performing two different tasks. The first experiment was set up to extract the contribution of uncertainty parameters to the dissimilarity perceived relatively to a reference sound, representing the nominal state of the product. The second experiment made it possible to assess a large set of stimuli and to determine its optimal partition. In all, these tests made it possible to determine which uncertainty parameters did affect sound perception and the perceptual space of the whole set of sounds.