Examensarbete

Nowadays, comfort in vehicles is a major key for marketing success. In terms of acoustics, comfort can be translated into sound quality of which annoyance is a major factor. Many studies have shown that sound as well as whole body or hand (or feet) vibrations may cause annoyance. Some studies show interaction effects of combined sound and vibration on vehicle sound quality. This thesis is an investigation of alternative methods for measuring sound and vibration comfort. The aim was to find possible matching effects between sound and vibration levels. A listening test was performed where the participants were presented two different sound levels in combination with two different vibration levels to their hands (steering wheel vibrations) and feet (floor vibrations). Comfort effects were measured in four different ways: - Rapid Affective Evaluation (Reaction Time) - Semantic scales (Questionnaire) - Self Assessment Mannequins (Questionnaire) - Facial Electromyogram (EMG) and Galvanic Skin Response (GSR) In addition, a tool for data processing of EMG and GSR data was constructed for the MATLAB environment. Repeated measures ANOVAs were performed to identify effects of stimuli levels. Self Assessment Mannequin results showed that participants felt happier and calmer with lower sound combined with lower vibration. Semantic scales showed statistical significance on variations in sound and vibration level. Effect of the visual stimuli was found on the participant ratings. Differences in sound level were found to have an influence on Reaction Time to different visual target stimuli. EMG for the Corrugator muscle showed that participants reacted with different frowning levels depending on sound-vibration visual stimuli combination. GSR results showed influence of visual stimuli on participant's activation.