Influence of vibration and listening environment on perception of recorded and BTPA generated interior car sounds

Abstract: The aim of this project is to get an understanding in what Binaural Transfer Path Analysis (BTPA) is in connection with the perceptual components for interior car sound. BTPA is an engineering tool for trouble shooting and sound design. The method describes the paths that the sound travels through a car body before coming into the interior of the vehicle. Normally the sound comes from the power train but it is also possible to include sound from wind noise.The thesis could be divided into two parts:- BTPA- Stimuli/reality perception (Listening tests in listening room/SoundCAR)The results from the listening tests shows that sound quality and perception is very individual and can be perceived with both positive and negative reactions. Vibration has large affects on the sound, both positive and negative. It is very individual when a person starts to feel discomfort caused by vibration, and the differences between the individuals are large. When comparing the sounds (Transient, idle, WOT) in both SoundCAR/listening room the sounds without vibration is perceived as:- Having a higher amount of tonality- Less powerful than the sounds with vibration- Less unpleasant compared to the sounds with vibration (SoundCAR)- To some extent less rough in the SoundCar- Less aggressive for transient and WOT sounds played in SoundCar and more aggressive for idle sounds played in the SoundCar- In general less attention demanding (SoundCar)- In general less reliable (SoundCar)In general the listening test in the SoundCar is perceived as more real/closer to reality compared to having the listening test in the listening room. The reality questions that were included in the test showed that there are slightly differences between sounds with vibration/without vibration. The feeling of being seated into a SoundCar with vibration is fairly convincing. If the result is expected to be closer to the reality the listening test should be in the SoundCar.