Sound levels, hearing habits and hazards of using portable cassete players

• Published in: Journal of sound and vibration Vol. 127; no. 3; pp. 521 - 528
• Main Authors: Hellström, P.-A., Axelsson, A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 22.12.1988
• ISSN: 0022-460X; 1095-8568
• DOI: 10.1016/0022-460X(88)90378-1

The maximum output sound pressure level ( SPL) from different types of portable cassette players (PCP's) and different headphones was analyzed by using KEMAR in one-third octave bands. The equivalent free-field dB(A) level (EqA-FFSL) was computed from the one-third octave bands corrected by the free-field to the eardrum transfer function. The dB(A) level varied between 104 dB from a low-cost PCP with supra-aural headphones (earphones with headbands and foam pads fitting against the pinna) to 126 dB from a high quality PCP with semi-aural headphones (small earphones without headbands to be used in the concha of the external ear). The cassette tapes used in this study were recorded with music, white noise, narrowband noise and pure tones. The equivalent and maximum SPL was measured in the ear canal (1 mm from eardrum) with the use of mini-microphones in 15 young subjects listening to pop music from PCP's at the highest level they considered comfortable. These SPL measurements corresponded to 112 dB(A) in free field. In a temporary threshold shift ( TTS) study, ten teenagers—four girls and six boys—listened to pop music for 1 h with PCP's at a level they enjoyed. The mean TTS value was 5–10 dB for frequencies between 1 and 8 kHz. In one subject the maximum TTS was 35 dB at 5–6 dB kHz. In order to acquire information about listening habits among youngsters using PCP's, 154 seventh and eighth graders (age 14–15) were interviewed. They used PCP's much less than expected during most of the year, but an increase was reported during the summer holidays.