ABSTRACT
The noise generated by the different profiles can then conveniently be considered in terms of multiples of threshold, i.e. the number of times the signal is greater than threshold. After a familiarization run with each vehicle through the site, the driver drove the vehicle along the entire length of the site with the left-hand wheels of the vehicle on the edgeline at a steady speed, while the experimenter operated the noise recording equipment. If the noise generated shows concentration in one region of the audible spectrum, this will be heard as a hum of a certain pitch, quite distinct from the broad-band noise generated by the vehicle. The overall level of in-vehicle noise is presented in terms of dB(A), a weighted average of the sound pressure level in each third-octave band which is biased towards those regions of the audible range which coincide with the range of the human voice.
