Quantification of sound quality for lawnmower radiated noise considering listening conditions

Abstract

In this study, we investigated an influence of listening conditions on the sound quality evaluation of lawnmower radiated noise and attempted to quantify the quality. Subjective evaluation tests were conducted using various lawnmowers equipped with engine or electric motor. In the active listening condition test, the participants operated the lawnmower by themselves and evaluated "discomfort" and "powerful" of the sound. They again evaluated the sound quality of the identical reproduced sound in a test room in the passive test. As the results, discomfort of the sound was significantly increased in the passive condition although powerful was almost same. Subsequently, we attempted to quantify these sound quality by using psychoacoustic metrics in each condition. The result indicated that both sound quality could be expressed very well using loudness and sharpness. Loud and high pitch sound was evaluated as more discomfort and loud and low pitch sound was more powerful. In addition, discomfort of the sound was clarified to be evaluated about 30% more in the passive condition than that in the active condition.