Towards noise control approaches more related to sound perception

Nowadays the requirements established by legislation and the demand of customers are forcing the earth moving machine manufacturers to face more efficiently the reduction of noise emitted by their products. In pursuing this objective it is fundamental to have tools enabling to evaluate the effectiveness of noise control actions. To cope with the standards the continuous equivalent A-weighted sound level LAeq is widespread used. Unfortunately this parameter is not satisfactory adequate in describing the perception of sound in terms of its quality. This aspect has become even more important and deeply investigated in automotive industry and its extension to earth moving machines should be considered in order to improve safety and comfort more efficiently. This paper describes a study undertaken to investigate how sounds at the operator's station of a skid steer loader, having the same LAeq but different spectra, are rated in terms of preference and annoyance.