The effects of noise on man

Indoor working and living environments are increasingly exposed to low-frequency noise sources. The well-known relationship between noise conditions and effects on human health requires the develop...

Effects of low-frequency noise on human cognitive performances in laboratory:

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Defining Health: Update From ASHRAE SGPC10 Committee, Interactions Affecting The Achievement Of Acceptable Indoor Environments

Book on noise effects on man covering audiometry, aural reflex, hearing damage risk, physiological responses, motor performance and speech communication

The effects of noise on man.

Artificial sound masking is increasingly used in open-plan offices to improve speech privacy and to reduce distraction caused by speech sounds. Most of the masking sounds are based on pseudorandom continuous noise filtered to a specific spectrum that should be optimized in respect with speech masking efficiency and comfort. The aim of this study was to increase basic understanding regarding the comfort. The second aim was to determine how well objective rating methods (15 different noise indices) predict the subjective ratings. Twenty-three subjects rated the loudness, disturbance, pleasantness, and six other subjective measures of 11 spectrally different noises in laboratory conditions. Speech was not present during the experiment. All sounds were presented at 42 dB LAeq within 50–10 000 Hz. Unexpectedly, the subjects were most satisfied with sounds having emphasis on low frequencies. A sound having a slope of −7 dB per octave increment resulted in the highest satisfaction. Changes in subjective ratings ...

Subjective and objective rating of spectrally different pseudorandom noises—Implications for speech masking design

The goal of this study was to investigate the effects of noise from building mechanical systems with time-varying fluctuations on human task performance and perception, and to determine how well current indoor noise rating methods account for this performance and perception. Six different noise conditions with varying degrees of time-varying fluctuations, many focused in the low frequency rumble region, were reproduced in an office-like setting. Thirty participants were asked to complete typing, grammatical reasoning, and math tasks plus subjective questionnaires, while being exposed for approximately one hour to each noise condition. Results show that the noise conditions with higher sound levels (greater than 50 dBA) combined with excessive low frequency rumble as well as those with larger timescale fluctuations (i.e., a heat pump cycling on and off every 30 seconds) were generally perceived to be more annoying than the other signals tested, although statistically significant negative relationships to task performance were not found. Other findings are (1) that the noise characteristics most closely correlated to higher annoyance/ distraction responses in this study were higher ratings of loudness followed by roar, rumble, and changes in time; and (2) that perception of more low frequency rumble in particular was significantly linked to reduced performance on cognitively demanding tasks. As for the ability of current indoor noise rating systems to match human performance or perception, none of the indoor noise rating methods evaluated were significantly correlated to task performance, but aspects of subjective perception such as loudness ratings were statistically related. Spectral quality ratings included with some noise rating methodologies were inconsistent with subjective perception, but other metrics such as RNC, L1 – L99 [LF ave], and LCeq – LAeq, were strongly correlated to rumble perception. The authors use the results to suggest a framework for an ‘ideal’ indoor noise rating method, but further research is required towards quantifying specific guidelines for acceptable degrees of time-varying fluctuations and tonalness.

Human performance and perception-based evaluations of indoor noise criteria for rating mechanical system noise with time-varying fluctuations

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AB-10-019: Human performance and perception-based evaluations of indoor noise criteria for rating mechanical system noise with time-varying fluctuations (1322-RP)

Cathleen C. Novak

Papers

Human performance and perception-based evaluations of indoor noise criteria for rating mechanical system noise with time-varying fluctuations

AB-10-019: Human performance and perception-based evaluations of indoor noise criteria for rating mechanical system noise with time-varying fluctuations (1322-RP)

Final Report for ASHRAE 1322-RP "Productivity and Perception Based Evaluation of Indoor Noise Criteria"