Annoyance prediction model for assessing the acoustic comfort at the operator station of compact loaders

Traditional noise control engineering methods are focused on reducing emitted A-weighted sound pressure levels to meet the legislative requirements; unfortunately the reduction of the exposure noise levels is not automatically associated to a real improvement of the acoustic comfort. Results from previous studies on these noise sources showed that Zwicker's loudness and sharpness are the parameters most related to the subjective perception of annoyance. These results were determined by applying the Sound Quality approach that also requires subjective listening tests which are very time consuming. This paper describes a series of experiments aimed at developing an annoyance prediction model which can be used for assessing the acoustic comfort at the operator station of compact loaders in working conditions. For this purpose, binaural measurements were carried out at the operator station of different loaders during the repetition of the same working cycle performed with two different materials (gravel and loam) and also without any material (simulated cycle). Then, the recorded sound stimuli were used in specific jury tests in order to assess the subjective annoyance. The same sound stimuli were also objectively analyzed in terms of acoustic and psychoacoustic parameters. Finally, a prediction model of annoyance for the noise signals at the operator station of compact loaders was developed following multiple regression technique.