Music, noise and hearing damage.

This article sets out the issues involved in the consideration of noise-induced hearing damage. Exposure to noise can lead to a shift in the hearing threshold, resulting in loss of hearing. This shift may be either temporary or permanent. When it is permanent it is usually irreversible and not all persons can be helped by hearing aids. Permanent shifting of the hearing threshold may be caused by exposure to high sound levels. Ratios between lengths of exposure and frequency levels are given. The measurement of sound levels and assessment of acoustic hazards are presently related to non-fluctuating sounds. Music fluctuates too much to be measured in these terms. Means have now been worked out to correlate the pressure of fluctuating sound (like music) with that of nonfluctuating sound (like industrial noise) and thus to equate statistics governing noise as an acoustic hazard with the hazard constituted by music. Table I shows the ambient sound levels which should be considered as unsafe per number of hours' exposure. I plead for better acoustic design in environmental planning and stress that people exposed to loud noise or music should undergo hearing tests regularly as the main preventive measure.