The equivalent sound pressure level—A reliable predictor for human responses to impulse noise?

Abstract

The effects of impulse noise on mood and on cardiovascular functions were studied in two separate experiments: 238 female and male subjects (30–60 years) participated in Experiment I (100 normotensive, 89 hypertensive, both subgroups were matched with regard to sex and self-estimated sensitivity to noise, and 49 normotensive subjects who felt indifferent to noise). In Experiment I pink noise, traffic noise and impulse noise (repetition rate: 2 shots/s) were applied with L Aeq of 62, 68, 74, and 80 dB as well as an impulse noise with an L Aeq of 71 dB but with repetition rates of 1, 2, 4, and 8 shots/s. These 16 noises each lasted 19 s and occurred randomly three times at intervals of 27–50 s. Experiment II was restricted to impulse noise where the L Aeq was stepwise increased from 62 to 80 dB either by elevating the peak levels or by increasing the repetition rates where each step equals at 3 dB. Generally, the responses to noise in all subgroups consisted of displeasure, heart rate acceleration, and vasoconstriction. The hypothesis that the equivalent sound pressure level is a suitable measure for the prediction of mood and cardiovascular responses was verified only for the vascular effects and as long as only one type of noise was considered.