A transformation was derived to convert sound-pressure levels referenced to an NBS-9A coupler to corresponding eardrum sound-pressure levels. It was found that the same transformation may be used for male and female adults and for both TDH-39 and TDH-49 earphones in MX-41/AR supra-aural cushions. It was determined that from 250-2000 Hz the transformation provides an eardrum sound-pressure level...

The inherent attenuation of a homogeneous viscous medium limits radiation propagation, thereby restricting the use of many high-frequency acoustic devices to only short-range applications. Here, we design and experimentally demonstrate an acoustic metamaterial localization cavity which is used for sound pressure level (SPL) gain using double coiled up space like structures thereby increasing th...

acoustic experimental data of irib (islamic republic of iran broadcasting) server room was taken to measure the acoustic noise characteristics of frequency and sound pressure level (spl). the purposes of this paper are measuring the noise pollution and its evaluation through the regulations. the measurements were taken in two stages. the first one was taken at 10 points by sound investigator 22...

background: noise pollution has a particular importance in quiet environments such as hospitals. the main objective of this study was to evaluate the effects of noise exposure on the auditory system, blood pressure and precision, concentration and other psycho-neural components. methods: this cross-sectional study was carried out in three large hospitals of shiraz, during the period of 2012 to ...

In-the-ear calibration of sound pressure level may be problematic at frequencies above 2 kHz, because the pressure can vary significantly along the length of the ear canal, due to reflection of sound waves at the eardrum. This issue has been investigated by measuring behavioral thresholds to tones in a group of human subjects (N = 61) for two different insertion depths of an insert earphone. Th...

background noise at intensive care units (icu) has an adverse effect on patients and icu staff. there are some evidences that sleep, recovery from critical illness and average background noise in hospitals as recommended by the us environmental protection agency (epa) and world health organization (who) should not exceed 30 a-weighted decibel (dba) and peaks during night time should be less tha...

Simultaneous audio and video were recorded of a silver perch Bairdiella chrysoura producing its characteristic drumming sound in the field. The background noise contribution to the total sound pressure level is estimated using sounds that occurred between the pulses of the silver perch sound. This background contribution is subtracted from the total sound to give an estimate of the sound pressu...