An investigation into automobile wind noise characteristics beyond loudness that affect people's responses to the sounds heard within the car

To guide automobile design, predictors of human response to wind noise are needed, and these are being developed through laboratory experiments. While it is well known that loudness plays a role in peoples' responses to steady-state wind noise, there is concern that spectral balance and other sound characteristics may also have effects. The test described in this paper was conducted in a sound booth where subjects listened to wind noise recordings and modified recordings presented over earphones. Sounds were recorded with binaural heads in three cars placed in different configurations in a wind tunnel. Recordings were decomposed into component parts that were amplified, attenuated, filtered, and reassembled to produce modified sounds. This signal modification approach was designed to vary sound characteristics while controlling loudness. The test was split into four parts, consisting of two paired comparison tests in which subjects rated their preference for sounds, and two Likert scale tests in which subjects rated sounds on an annoyance scale. The changes in sound characteristics that accompany changes in responses are compared to the changes in loudness that accompany similar changes in responses. The usefulness of some sound metrics, solely or in combination, as predictors of the responses is also explored.