SUBJECTIVE ASSESSMENT OF DIESEL VEHICLE NOISE

This paper summarises two methods used to quantify the subjective assessment of diesel engine noise. The results of each test are evaluated and compared. One method is conventional, where the subjects are presented with a sequential recording of engine noise and rate such noise on a 0 to 9 scale of preference. The second method is interactive. In this method, the subject is provided continually with signals from which he or she can construct the stimulus for assessment. In both, the subjects are asked to rate engine noise with graded levels of boom and impulsive characters. The experiments took place in a van cab at cruise speed, and the relative importance of impulsiveness (kurtosis) and the overall sound level in dB(A) were assessed. The results from the subjective score experiment fell between the two closely spaced results from the interactive experiment. When individual subject's scores were compared with the same objective measurements considerable scatter was observed, mainly due to peoples aversion to either boom or high frequency noise. For the covering abstract see IRRD 869232.