Temporal and spectral characteristics of BSR noises and influence on auditory perception

BSR (Buzz, squeak and rattle) noises have become increasingly important and currently have a significant influence on vehicle quality now that other noise sources have been decreased. To prevent their generation, the cause of BSR noises must be classified depending on their temporal and spectral characteristics. Their influence on acoustic comfort should also be quantified for evaluation. This information is crucial for suggesting appropriate engineering solutions to minimize noise generation. In this study, BSR sounds were classified depending on their periodicity (occurrence per seconds) and spectrum contents (sharpness). For continuous sounds, such as squeaking sounds, the perceived annoyance was represented accurately by the loudness of the sound. For sporadic sounds, such as buzzing and rattling noises, the temporal magnitude variation significantly influences the annoyance. Prony's method was used to quantify exponentially decreasing impact noises. The attenuation derived from Prony’s method represented how fast BSR noises decay with time. After performing auditory tests for BSR noises measured in actual vehicles, the rating on the annoyance level was determined. BSR sounds that decayed quickly caused annoyance.