Exploring the Impact of Nonlinear Distortion on Perceived Musical Gestures and Intentions

Distortion is a defining timbral characteristic in many current popular music genres and arises from nonlinear processing that introduces complex spectral changes such as increased brightness and auditory roughness. Despite its cultural and expressive significance, the perceptual, affective and embodied effects of distortion remain underexplored. This study investigates how spectral modifications induced by nonlinear distortion on guitar chords influence listeners’ perception of the emotional valence, physical effort, movement amplitude, and symbolic sound categorization. Using 20 distorted electric guitar stimuli generated with an implementation of the Boss DS-1 pedal, eight participants rated six perceptual and affective dimensions. Acoustic descriptors (spectral centroid and auditory roughness) were computed for each stimulus to model timbral changes. Results indicate that increased roughness correlates with more negative emotional valence and trends toward greater perceived effort, while brightness strongly relates to Bouba/Kiki judgment. Professional experience in sound-related fields and frequency of musical practice were also found to increase valence and amplitude ratings. These findings show that specific acoustic features produced by non-linear distortion differentially shape judgments of emotional valence, physical effort, and sound-symbolic categorization, with these effects modulated by listeners’ prior experience. Future work will extend the descriptor set and aims to inform a multidimensional model of distorted timbres.