Passenger ride quality within a noise and vibration environment

The subjective response to noise and vibration stimuli was studied in a ride quality simulator to determine their importance in the prediction of passenger ride quality. Subjects used category scales to rate noise discomfort, vibration discomfort, both noise and vibration discomfort, and overall discomfort in an effort to evaluate parametric arrangements of noise and vibration. The noise stimuli were composed of octave frequency bands centered at 125, 250, 2,000 and 4,000 Hz, each presented at 70, 75, 80, and 85 dB(A). The vertical vibration stimuli were 5 Hz bandwidth random vibrations centered at 3, 5, 7, and 9 Hz, each presented at 0.03, 0.06, 0.09, and 0.12 grms. Analyses were directed at (1) a determination of the subject's ability to separate noise and vibration as contributors to discomfort, (2) an assessment of the physical characteristics of noise and vibration that are needed for prediction of ride quality in this type of multifactor environment, and (3) an evaluation of the relative contribution of noise and vibration to passenger ride quality.