Affect as a Component of Perceived Sound and Vibration Quality in Aircraft

The concept of product sound quality is becoming an integral component of product development and design. The research presented in this thesis test the notion that affective reactions (i.e. positive-negative feelings) are a major determinant of perceived sound quality. A secondary aim is to test the effects of additional modalities (vision and tactile senses) on affective reactions. Paper I focused on assessing affective reactions to and cognitive evaluations of set of interior aircraft sounds. An additional aim was to study the relationship between affective reactions and physical measures. In addition, the relation between affect, annoyance and overall rated quality was investigated. Paper II focused on comparing affective reactions and affective evaluations. To further test the link between physical properties and affect, a different set of sounds was also included. Paper III highlighted the affect-physical measures relationship by using a set of systematically synthesized sounds. Paper III also more explicitly addressed the correlation between affective reactions and annoyance ratings. In Paper IV attention was directed to multimodal (sound and vibration) perception and how sound and vibration combinations influenced affective reactions and preference. Finally, Paper V examined the combined effect of three types of stimuli, auditory, tactile and visual on affective reactions, sound quality evaluation, and perceived presence. The results provided strong support for the hypothesis that affective reactions to auditory stimuli can be described by the two fundamental affect dimensions of valence (positive-negative) and activation (deactivated-activated). The results further showed that valence and activation had different psychoacoustical determinants. The valence dimension was related to loudness, whereas the activation dimension should be related to sharpness (positive correlation) and tonal content (negative correlation). In addition, correlational analyses showed that a large component of the variance in quality ratings was accounted for by the valence and activation measures. Another major finding was that multimodal affective perception of an environment (e.g. auditory and tactile/visual) differed from unimodal perception (auditory only), where multi-modal perception has both discounting and augmenting effects on affective reactions and sound quality evaluation. Taken together, the current research suggests that affective reactions are fundamental to perception of auditory stimuli and is thus an integral part of the evaluation of sound quality. In addition, both sound characteristics and input from non-auditory modalities influence affective reactions in an aircraft environment. One approach to improve sound quality is to investigate affective reactions to product sounds.