Investigating the Psychoacoustic Characteristics of Absorbents used in Common Earmuffs: A Laboratory Study

Introduction: 
In addition to having auditory effects, sound also has nonauditory effects. Acoustic Annoyance is one of the nonauditory effects of sounds which are construed as psychoacoustic characteristics. The study at hand was undertaken to investigate the psychoacoustic characteristics of absorbents used in common earmuffs.
Materials and Methods: 
In this study, four earmuffs prevalent in industries were used. The psychoacoustic characteristics of loudness and sharpness were measured and analyzed in sound levels of 75, 85, and 95 dB using an impedance tube and Va-Lab 4 software with and without absorbers. The results were analyzed with SPSS-26 software.
Results: 
Results showed that the highest and the lowest increase in loudness were attributed to the EM-101 and the EM-104, respectively. In addition, with the increase in the sound level, the loudness increased. Furthermore, in 85 dB, there was no significant relationship between loudness and earmuff absorber only in the case of the earmuff EM-103. Furthermore, the highest and the lowest increase in sharpness were, respectively, attributed to the EM-101 and the EM-103. Only in the samples of EM-103 and EM-104 earmuffs at the level of 75 dB, there was no significant relationship between sharpness and earmuff absorber.
Conclusion: 
Earmuffs used in industries showed different performances against the loudness and sharpness of the sound. In other words, the quality and the structure of earmuff absorber play noteworthy roles in decreasing the qualitative parameters of sound.