Speech Quality Tests of In-Car Communication Systems

In-Car Communication Systems (ICC systems) are intended to improve the communication between driver and co-driver in vehicles. The hardware effort can be limited as the components like microphones typically used for hands-free communication and rear seat loudspeakers are already available. The driver's voice is picked up by the microphone and played back via the rear loudspeakers. Such systems significantly improve communication quality especially at higher speeds assuming that the quality is not noticeably impaired by long propagation delay, unnatural sound of speech or acoustical feedback ("howling"). Such systems can be characterized by speech intelligibility and speech quality tests. The main focus of this contribution is the adaptation of an objective method to determine speech quality for such systems.