Subjective Quantification of Wind Buffeting Noise

It is well known that customer perception of the annoyance of steady-state wind noise can be fairly well characterized by calculating the loudness of such sounds. Commonly used is the ISO532B or Zwicker method [1]. What is not known, however, is how a customer would react to time-varying wind noise. Such situations can occur when a vehicle experiences cross-wind conditions on the highway. Turbulent air flow generated by either a passing vehicle or when traveling in the wake of another vehicle can cause the wind noise to take on time-varying characteristics. The time-varying wind noise created by such situations is commonly referred to as “buffeting.” Customer complaint field data indicates that wind buffeting is a source of annoyance, but the level of the effect has never been quantified. In this study, binaural sounds were recorded inside an aeroacoustic wind tunnel. Varying degrees of buffeting were simulated using a “blocker” vehicle situated in front of the test vehicle. Once the data was collected, a designed experiment was conducted in which a paired comparison jury listening evaluation revealed that the wind buffeting noise can have a significant impact on the annoyance of the wind noise when sounds are presented which vary in both buffeting and loudness. The buffeting impact is roughly equal to 1/3 the effect that an increase or decrease in loudness would have for the sample set used in this study. Additionally, a paired comparison evaluation was conducted in which the subjects selected loudness-equalized sounds based on the buffeting aspect alone. The resulting subjective responses are currently being used for objective measures development work