SOUND QUALITY OPTIMISATION OF DIESEL ENGINE CARS - A FIRST STEP IN THE DIRECTION OF VIRTUAL DEVELOPMENT OF SOUNDPROOFING PACKAGES

摘要

The paper focuses on the sound quality investigation of new-generation diesel engine vehicles: a wide range of them was considered, from B to D segment as well as commercial ones. Idling conditions were selected and all vehicles acoustically characterized with objective measurements; an evaluation of the global acoustic transparency of the vehicles was also performed, together with a first subjective analysis. Vehicles were then equipped with a new-generation acoustic treatment, fitted to OEM requests and focussed to the final sound quality appearance as well as to the later treatment feasibility. A great improvement was achieved, in terms of acoustic transparency, overall levels and spectra in idle conditions, as well as of the vehicles' subjective character. A time-domain analysis was performed and a first correlation between sound quality parameters and subjective perception was defined.