AMBIENT NOISE-LEVELS IN AUDIOMETRIC TEST ROOMS USED FOR CLINICAL AUDIOMETRY

Recently, the American National Standards Institute (ANSI) has specifi ed (ANSI 83.1-1991) maximum permissible ambient noise levels (MPANLs] allowed in an audiometric test room that would produce negligible mask ing of pure tones presented down to O-dB HL for two test conditions (e ars covered, ears not covered) and three test frequency ranges (125-80 00 Hz, 250-8000 Hz, 500-8000 Hz]. In the present study, octave band am bient noise sound pressure levels were measured in 136 audiometric tes t rooms used for clinical audiometry and compared with the ANSI octave band MPANLs for each test condition and frequency range. For the ears covered condition, about 50% of the rooms were in compliance (passed) with the MPANLs for the 125-8000 Hz and 250-8000 Hz range and 82% for the 500-8000 Hz range. For the ears not cowered condition, only about 14% of the rooms passed for the 125-8000 Hz and 250-8000 Hz range and 37% passed for the 500-8000 Hz range. The primary cause of the low pa ss rate for each test condition and frequency range was attributed to low frequency (125-500 Hz) ambient noise presumably from the ventilati on system.