Tonal Annoyance Metric Development for Automotive Electric Vehicles 2019-01-1467
Historical metrics intended to drive the development of vehicle powertrains have focused on sounds that are characteristic of IC engines. The interior noise contribution of the propulsion system in electric vehicles has significantly more tonal noise than their IC engine counterparts. This tonal noise is not adequately represented by current propulsion systems metrics. While metrics exist today that were developed to represent the presence of tones in sounds most have focused on the level aspect of the tones relative to the surrounding noise or masking level, some examples include tonality, tone-to-noise ratio, and prominence ratio. A secondary, but also important aspect of tones is the annoyance as a function of frequency. This paper will highlight the development of a tonal annoyance weighting curve that can be used to account for the frequency aspect of tonal annoyance relative to electric vehicles. This weighting curve can then be used in conjunction with the current tonal metrics to represent perceived tonal annoyance of electric vehicles. The benefit of the tonal annoyance weighting curve is demonstrated by comparing tonal metrics calculated with the weighting curve applied to the subjective preference of electric vehicle sounds as measured in a jury study.
Glenn Pietila, William Seldon, Timothy Roggenkamp, Timothy Bohn
Noise and Vibration Conference & Exhibition