title: Acceptable range of speech level in noisy sound fields for young adults and elderly persons.
abstract: The acceptable range of speech level as a function of background noise level was investigated on the basis of word intelligibility scores and listening difficulty ratings. In the present study, the acceptable range is defined as the range that maximizes word intelligibility scores and simultaneously does not cause a significant increase in listening difficulty ratings from the minimum ratings. Listening tests with young adult and elderly listeners demonstrated the following. (1) The acceptable range of speech level for elderly listeners overlapped that for young listeners. (2) The lower limit of the acceptable speech level for both young and elderly listeners was 65 dB (A-weighted) for noise levels of 40 and 45 dB (A-weighted), a level with a speech-to-noise ratio of +15 dB for noise levels of 50 and 55 dB, and a level with a speech-to-noise ratio of +10 dB for noise levels from 60 to 70 dB. (3) The upper limit of the acceptable speech level for both young and elderly listeners was 80 dB for noise levels from 40 to 55 dB and 85 dB or above for noise levels from 55 to 70 dB.
authors: Environmental Acoustics Laboratory, Graduate School of Engineering, Kobe University Rokko, Nada, Kobe 657-8501, Japan. hayato@kobe-u.ac.jp
authors: Hayato
authors: H
authors: Sato
authors: Masayuki
authors: M
authors: Morimoto
authors: Ryo
authors: R
authors: Ota
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000704:Analysis of Variance; D001302:Audiometry, Speech; D001309:Auditory Threshold; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009622:Noise / Q000009:adverse effects*; D010470:Perceptual Masking; D013065:Speech Intelligibility; D013067:Speech Perception; D055815:Young Adult