Factors Governing Acoustical Comfort In Vehicle Compartments
Doctoral thesis, 2012
A pleasant interior sound field is an essential comfort criterion for vehicle occupants.
The pleasantness is mainly influenced by a low overall sound pressure
level. Further minimization of driving noise, however, is constricted on the
lower end by physical limitations. Moreover, driving noise conveys information
about the current driving condition, the vehicle state and environmental aspects.
Auditory feedback is therefore indispensable for a certain vehicle/driver
interaction. The perception of vehicle noise is further dependent on contextual
aspects. The experience and the expectation of vehicle occupants regarding
the car and its acoustical characteristics in particular driving conditions are
determining for an appreciation of these characteristics.
The present thesis deals with various aspects of subjectively perceived
acoustical comfort in vehicles. First of all, physical and notably acoustical
parameters of in-vehicle driving noise are taken into account, particularly as
regards the composition of driving noise based on the main noise contributors
powertrain, wind and tires. In addition to the assessment of driving noise,
room-acoustical properties of vehicle compartments are included in order to
quantify the impact of room acoustics on communication between the vehicle
occupants. On the other hand, contextual aspects such as the transfer of
information via acoustical events are considered. The outcome of this work
may be utilized by researchers and developers of vehicle sound fields for an
improvement of customer-relevant acoustical target setting. Additionally, it
outlines some basic concepts how to create pleasant in-vehicle sound fields
based on sound quality approaches and speech communication aspects.