LISTENING TO MUSIC WITH EARPHONES - AN ASSESSMENT OF NOISE EXPOSURE

A noise exposure assessment was made for 45 test subjects using person al cassette players (PCP) and earphones. New information about the rel ation of background noise level and the listening level was found in f ield and laboratory studies with test subjects. An acoustic coupler wa s designed for earphone sound level measurements and the maximum conti nuous sound levers from 12 PCPs were measured. The highest sound level s at maximum volume settings of the PCPs ranged from 90 dB to 104 dB. Comfortable music levels in the quiet ranged from 52 dB to 88 dB, the average being 69 dB. In the laboratory with background noise the music levels ranged from 69 dB to 95 dB. In the field study the average lis tening level was 82 dB and the average calculated weekly exposure (L(E P,w)) 75 dB. The weekly noise exposure of 15% of the test subjects exc eeded 85 dB in the field study. All the PCPs examined were able to pro duce high sound levels but the typical listening levels chosen by PCP users were not alarming. The music level was on average set to exceed 85 dB when the background noise level was 72 dB. Some hearing ross ris k would be expected when PCPs are used in noisy conditions at work or among traffic.