Subjective response to very low-frequency vibration.
Using intensity matching and magnitude estimation techniques, seated subjects made judgments of the perceived intensity of vertical, short-duration (30-60s), high-amplitude, low-frequency (0.25-4.0 Hz) vibration. Intensity matching (setting comparison frequencies to match the perceived intensity of a standard frequency) produced equal intensity contours that indicated minimum sensitivity in the vicinity of 1 Hz. Frequencies both above and below 1 Hz were judged subjectively equal at progressively lower accelerations. In the magnitude estimation procedure, subjects assigned values of subjective magnitude to various levels of a given frequency in proportion to the subjective magnitude of a standard level at the same frequency. For each of seven frequencies sampled, the data produced straightline functions on log-log plots of subjective magnitude vs. acceleration. Data from both the intensity matching and magnitude estimation experiments were combined to provide a model that allowed the extension of various vibration exposure criteria down to 0.25 Hz-using data at 4 Hz as a basis for extrapolation-even at intensity levels beyond the capabilities of available vibration devices.
D000054:Acceleration; D000337:Aerospace Medicine; D006801:Humans; D008297:Male; D011930:Reaction Time; D012677:Sensation; D014732:Vibration