Automotive Aeroacoustic Sound Quality

Aeroacoustic noise sources are becoming increasingly important in the vehicle environment. Research has suggested that for electric vehicles, the predominant focus in development effort shifts from powertrain noise, to masking noises such as road and aeroacoustic. Despite this, the consumer perception of automotive aeroacoustic sound quality is a remarkably under researched field; few examples of literature have previously investigated this area, with fewer still employing qualitative techniques. This publication summarises a two phase research project. Initially, focus groups were conducted, to gather information on the ways in which a variety of consumer demographics perceive aeroacoustic sound quality. Rigorous grounded theory analysis of the discussions identified six core categories: the perceived acoustic character of the sound, the conditions and environment, the balance of the aeroacoustic sound (spatially, spectrally and relative to other sounds), its noticeability, the expectation of the consumer, and finally their emotional response. In the second phase, quantitative semantic differential listening studies were carried out using a vehicle simulator. Four principal components were found to explain 85% of the total variance of nine semantic scales: how intrusive the subjects believed the sound to be, how aggressive the aeroacoustic noises were, whether the sounds met the subjects expectation, and finally whether the sounds were perceived as spatially balanced by the participant. This study confirms that traditional aeroacoustic performance quantification methods employed by automotive manufacturers, may not be suitable for evaluating a number of the key factors of aeroacoustic sound quality perception. The study also demonstrates the use of a vehicle simulator to assess individual acoustic sources in the presence of other sounds