An Evaluation Method of Combined Effects of Infrasound and Audible Noise

Abstract

A psychophysical experiment was conducted to investigate an evaluation method for the combined effects of infrasound and audible noise. In the experiment, subjective rating of 80 mixed noise stimuli were obtained from 15 subjects on 22 semantic-differential-type scales. The stimulus noise conditions were mixtures of one of eight pure tones at 5, 10, 20, and 40 Hz and one of eight 1/3 octave band noises with centre frequencies 63, 125, 250, and 500 Hz. The rating data were subjected to a principal component analysis and yielded two principal components, these were interpreted as the perceptual components of infrasound and audible noise respectively. On the basis of this result, a psychophysical model was proposed to make two-dimensional predictions of subjective ratings from the physical variables of the noise stimuli. Following this model, a best weighting curve, in combination with the A-weighting curve and their regression weights, were estimated. The results showed that the psychological model successfully described the rating data.

A Study on the Relationship between Subjective Unpleasantness and Body Surface Vibrations Induced by High-level Low-frequency Pure Tones

“…This indicates that noise content at lower frequencies should be given more importance in evaluating high-level low-frequency noise. Inukai et al 25) previously proposed the LF-weighting characteristic for evaluating lowfrequency noise. They modified the low-frequency part of the A-weighting characteristic by taking into consideration not only the effect of hearing sensation but also the effects of vibratory and oppressive sensations.…”

Measurement of Human Body Surface Vibrations Induced by Complex Low-Frequency Noise Composed of Two Pure Tones

“…To assess the effects of low-frequency noise from a medical viewpoint, noise-induced vibrations should be measured not only on the body surface but also in the inner body, and the characteristics of noise-induced vibration must be quantitatively related to the prevalence and/or stages of adverse health effects such as vibroacoustic disease. Already, some frequency-weighting curves, such as the LF-weighting curve [16] and the G-weighting curve [17], have been proposed. Because they have been designed on the basis of the human psychological and perceptual responses to low-frequency noise, they are considered to be useful and effective in assessing perceptions of noise.…”

A New Approach to Assess Low Frequency Noise in the Working Environment.

“…(25-50 Hz) in the A-weighting curve, about 13.5 dB/oct. (20-50 Hz) in the LF-weighting curve 8) , and about 12 dB/oct. (1-20 Hz) in the G-weighting curve 9) .…”

“…To assess high-level low frequency noise in the working environment appropriately, the adverse extra-aural effects should be taken into account, but the A-weighting curve, which is a standardized weighting curve 2) for measuring and assessing noise, and some weighting curves focusing on low frequency noise, such as the LF-weighting curve 8) and the G-weighting curve 9) , are not related to the extra-aural effect, because they are designed on the basis of the human psychological and perceptual responses to noise. Thus it is doubtful whether the frequency-weighting characteristics in these existing weighting curves are suitable for assessing the extra-aural effect.…”