Analysis of Determining Parameters of Acoustical Comfort Inside Vehicles 2011-01-1686

The description of subjectively perceived acoustical comfort inside vehicle compartments is a complex challenge. On the one hand, it depends on physically measurable events like acoustical stimuli with a defined sound pressure level and frequency distribution. On the other hand, it is also strongly dependent on further factors like the customer's individual expectations, the previously made experiences and other contextual influences. Furthermore, many different driving conditions have to be considered for a customer-related assessment of driving comfort.

In this paper, the mechanisms of acoustical comfort inside vehicle compartments are described on basis of various measurements, listening tests and qualitative assessments. The acoustical properties of driving noises at various driving conditions were taken into account as well as room-acoustical parameters of vehicle interiors and factors of speech communication between passengers. An interview-based qualitative assessment did confirm the importance of speech communication aspects for the comfort experience and well-being of both driver and passengers. These aspects are for example the speech intelligibility, the quality of conversational speech and further the increase in the vocal effort during a conversation in the presence of driving noises. In addition, the characteristics of driving noises at stationary and non-stationary driving conditions were under examination, both in a listening studio and on a test track. The results of the listening tests and customer surveys are connected to acoustical and psychoacoustical parameters to identify the customer-preferred properties of driving noises. This identification is further itemized to an empirically determined optimal ratio between the main noise components (powertrain-induced, chassis-induced and wind-induced noises). As a result of all these investigations, a prediction model of acoustical comfort will be developed in the future.