OBJECTIVES: The purpose of this study was to determine daily noise doses and 8-hour time weighted averages for rock band musicians, crew members, and spectators during a typical rehearsal and performance using both Occupational Safety and Health Administration (OSHA) and National Institute of Occupational Safety and Health (NIOSH) measurement criteria. DESIGN: Personal noise dosimetry was completed on five members of a rock band during one 2-hr rehearsal and one 4-hr performance. Time-weighted averages (TWA) and daily dose values were calculated using both OSHA and NIOSH criteria and compared to industry guidelines for enrollment in hearing conservation programs and the use of hearing protection devices. RESULTS: TWA values ranged from 84.3 to 90.4 dBA (OSHA) and from 90.0 to 96.4 dBA (NIOSH) during the rehearsal. The same values ranged from 91.0 to 99.7 dBA (OSHA) and 94.0 to 102.8 dBA (NIOSH) for the performance. During the rehearsal, daily noise doses ranged from 45.54% to 106.7% (OSHA) and from 317.74% to 1396.07% (NIOSH). During the performance, doses ranged from 114.66% to 382.49% (OSHA) and from 793.31% to 5970.15% (NIOSH). CONCLUSIONS: The musicians in this study were exposed to dangerously high levels of noise and should be enrolled in a hearing conservation programs. Hearing protection devices should be worn, especially during performances. The OSHA measurement criteria yielded values significantly more conservative than those produced by NIOSH criteria. Audiologists should counsel musician-patients about the hazards of excessive noise (music) exposure and how to protect their hearing.

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---The effects of thermal transients after write, changes in stress-magnetostriction products and dynamic domain instabilities on popcorn noise probabilities in micro Flexhead® components were studied., It was observed that popcorn noise probabilities in micro Flexhead® components increase as the write current duration increases, until they saturate, with a specific write current amplitude. With increasing write current amplitude, the initial rate of change of noise probability with write current duration increases. In some cases where the resultant stress-magnetostriction products in micro Flexhead® components are negative, popcorn noise probabilities were observed to increase exponentially as functions of applied stress gradients. High rates of occurrence of dynamic domain instabilities have also been correlated with micro Flexhead® components that have high popcorn noise probabilities. Therefore. high probabilities of popcorn noise in micro Flexhead® components are caused by the combined effects of thermal transients after write, changes in stress-magnetostriction products and dynamic domain instabilities. Finally. an inductance fluctuation measurement technique was shown to be useful in quickly detecting micro Flexhead® components that are susceptible to popcorn noise.