title: Effect of Noise on Vocal Loudness and Pitch in Natural Environments: An Accelerometer (Ambulatory Phonation Monitor) Study.
abstract: OBJECTIVE
  This study investigated the effects of environmental noise on the production of vocal intensity and fundamental frequency using an accelerometer.
  
  
  METHODS
  Twenty-four vocally healthy young adults (12 men and 12 women, aged 19-22 years) recorded a monologue passage using KayPENTAX (Montvale, NJ, USA) Ambulatory Phonation Monitor (model 3200) under three natural environmental conditions in a randomized order: a quiet room (mean noise, 35.5 dBA), room with moderate level of noise (mean noise, 54.5 dBA), and a room with high noise (mean noise, 67.5 dBA).
  
  
  RESULTS
  Both gender groups showed significant increases in the mean vocal intensity, fundamental frequency, and perceived vocal effort in the high-noise environment than in the other two conditions. No significant difference was found in the vocal intensity between the quiet and moderately noisy environment except in the fundamental frequency in the female group.
  
  
  CONCLUSIONS
  This study showed that the use of accelerometer for laryngeal signal recordings could be a useful tool for measuring phonation without being affected by the background noise. The findings also support the recommendation that noise levels for conversation should be kept <50-55 dB to maintain speech intelligibility.
authors.affiliation: Division of Speech and Hearing Sciences, Voice Research Laboratory, The University of Hong Kong, Pokfulam, Hong Kong. Electronic address: eyiu@hku.hk.
authors.forename: Edwin M-L
authors.initials: EM
authors.lastname: Yiu
authors.affiliation: Division of Speech and Hearing Sciences, Voice Research Laboratory, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Priscilla P S
authors.initials: PP
authors.lastname: Yip
mesh_terms: D061725:Accelerometry / Q000295:instrumentation*; D000223:Adaptation, Psychological; D004777:Environment; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007830:Larynx / Q000502:physiology*; D008144:Loudness Perception; D008297:Male; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D009622:Noise; D010699:Phonation; D010898:Pitch Perception; D013065:Speech Intelligibility; D013068:Speech Production Measurement; D013997:Time Factors; D014833:Voice Quality; D055815:Young Adult
keywords: Accelerometer; Background noise; Lombard effect