THE RELATIONSHIP OF SPEAKER INTELLIGIBILITY TO THE SOUND PRESSURE LEVEL OF CONTINUOUS NOISE ENVIRONMENTS OF VARIOUS SPECTRA AND OCTAVE-BAND WIDTHS

1957 ◽  
Author(s):  
GILBERT C. TOLHURST
2003 ◽  
Vol 22 (1) ◽  
pp. 27-32
Author(s):  
Takuya Fujimoto

Putting an ear close to a vibrating structure like a wall or a floor, we are able to hear structure-borne sounds clearly, but the loudness of such sounds has never been studied quantitatively. In this study, subjective experiments were carried out in order to obtain the relationship between loudness and the vibration amplitude of the ear's contact surface at low audible frequencies. The main result of this study is that the loudness of a structure-borne sound is almost equal to that of an air-borne sound with a sound pressure level 20 dB higher than the vibration velocity level (ref=5×10−8 m/s) of the surface. According to this result, the loudness of the structure-borne sound heard directly can be evaluated as a sound pressure level derived from the measured vibration amplitude of the structure.


Author(s):  
Hadi ALIMORADI ◽  
Ruhollah FALLAH MADAVARI ◽  
Mahsa NAZARI ◽  
Reza JAFARI NODOSHAN ◽  
Mohammad Javad ZARE SAKHVIDI ◽  
...  

Introduction: Loud noise is one of the harmful factors that affects industry workers seriously. In the steel industry, a wide range of equipment and machinery are used in the production processes, which are considered as the sources of annoying noise. Sound has immediate and delayed harmful effects on the process of concentration and increases blood pressure. The aim of this study was to investigate the effect of noise in two different ranges in the control and case groups within the authorized (between 60 to 85 dB) and unauthorized (above 85 dB) categories in the steel industry. Methods: This cross-sectional study was conducted among 300 workers in Isfahan Steel Industries. Environmental sound assessment was performed to determine the distribution of sound pressure level according to the ISO 9612 standard in the company's production units. In this method, the number of exposed people, the exposure time, and the weight factor corresponding to the sound pressure level were calculated in 30 minutes. The DASS-42 and Harmon Jones (DARQ) questionnaires were used to predict the mental state of the participants and to measure the severity of mood swings and arousal. The collected data were analyzed using SPSS statistical software (ver22). Results: Based on the findings, age had a significant effect on depression, marital status had a significant effect on anxiety, and work shift had a significant effect on the level of stress and cognitive dissonance of employees. The stress mean was significantly higher in the case group (14.40 ± 1.66) than the control group (p <0.001). This indicates the effect of sound intensity level on the increase of stress and cognitive dissonance of workers in a noisy environment. With increasing exposure to sound, the participants’ stress decreased (p <0.05). Conclusion: Considering the positive and significant relationship of noise level with stress and cognitive inconsistency of workers in the case group, it is necessary to take effective preventive measures to prevent psychological harm and maintain the workers' health in this industry. In order to reduce noise, a number of applicable solutions have been proposed including spatial planning, selection of suitable materials, control of noise pollution related to outdoor construction, control of noise pollution related to indoor construction, and training.


1969 ◽  
Vol 12 (1) ◽  
pp. 193-198 ◽  
Author(s):  
Ralph L. Shelton ◽  
William B. Arndt ◽  
Albert W. Knox ◽  
Mary Elbert ◽  
Linda Chisum ◽  
...  

A group of 21 subjects with well-fitted speech bulbs was compared for nasal sound pressure level (SPL) with a group of 13 subjects having moderate deficiency of palatopharyngeal closure. The difference in mean measures for the two groups was statistically significant. Correlation coefficients are reported for the relationships between nasal SPL and both a cinefluorographic measure of palatopharyngeal closure and several articulation measures.


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