Study on audiometer calibration at the extended high-frequency range 8–16 kHz

2021 ◽  
pp. 095745652110526
Author(s):  
Tarek M. El-Basheer
Keyword(s):  
Hearing Loss ◽  
High Frequency ◽  
Sound Pressure ◽  
Uncertainty Estimation ◽  
Sound Level ◽  
Pressure Level ◽  
Physical Parameters ◽  
Frequency Range ◽  
Measurement Traceability ◽  
Level Meter

Audiometry is a branch of acoustical measurements that concentrated on testing the devices related to hearing and used in medical part such as audiometer. It is substantial to calibrate the audiometer to assure the measurement traceability and to safe human health. So, it is considered as a major claim. The importance of calibration comes from the request for advanced instrument to test accurately the hearing loss for human, especially for those people who might be at risk due to noise. The conventional audiometry covered from 125 to 8 kHz, while the extended high-frequency (EHF) audiometry above 8 up to 20 kHz, the last-mentioned type may be useful in early diagnosis of hearing loss. The audiometer calibration performed using ear simulator, standard or working microphone, sound level meter, and frequency analyzer according to IEC60645-1. The physical parameters such as sound pressure level, frequency and distortion may be affected by environmental conditions such as temperature change. The gained results observed that the measured value of all the tests performed was affected by temperature variation. There were deviations observed from each performed test’s nominal values in the calibration process as the temperature varies from 16 to 40°C. So, this is a detailed study for the significance, method, and uncertainty estimation for audiometer calibration covering the EHF ranges within the temperature from 16 to 40°C.

Research of Possibilities of Using the Recycled Materials Based on Rubber and Textiles Combined with Vermiculite Material in the Area of ​​Noise Reduction

2014 ◽  
Vol 1001 ◽  
pp. 171-176 ◽  
Author(s):  
Pavol Liptai ◽  
Marek Moravec ◽  
Miroslav Badida
Keyword(s):  
Absorption Coefficient ◽  
Standing Wave ◽  
Sound Pressure Level ◽  
Sound Absorption ◽  
Sound Pressure ◽  
Sound Level ◽  
Pressure Level ◽  
Sound Absorption Coefficient ◽  
Physical Parameters ◽  
Materials Research

This paper describes possibilities in the use of recycled rubber granules and textile materials combined with vermiculite panel. The aim of the research is the application of materials that will be absorbing or reflecting sound energy. This objective is based on fundamental physical principles of materials research and acoustics. Method of measurement of sound absorption coefficient is based on the principle of standing wave in the impedance tube. With a sound level meter is measured maximum and minimum sound pressure level of standing wave. From the maximum and minimum sound pressure level of standing wave is calculated sound absorption coefficient αn, which can take values from 0 to 1. Determination of the sound absorption coefficient has been set in 1/3 octave band and in the frequency range from 50 Hz to 2000 Hz. In conclusion are proposed possibilities of application of these materials in terms of their mechanical and physical parameters.

scholarly journals THICKNESS INFLUENCE ON ABSORBING PROPERTIES OF STRATIFIED COMPOSITE MATERIALS

2015 ◽  
Vol 21 (4) ◽  
pp. 28-34
Author(s):  
IULIANA IAȘNICU (STAMATE) ◽  
OVIDIU VASILE ◽  
RADU IATAN
Keyword(s):  
Composite Material ◽  
Sound Pressure ◽  
Layered Composite ◽  
Sound Level ◽  
Pressure Level ◽  
Sound Level Meter ◽  
Absorbing Materials ◽  
Absorbing Material ◽  
Study Case ◽  
Level Meter

Plates known as sound absorbing materials: textiles recovered fabrics plus polyethylene are made layered composite material intended to be used to encapsulate industrial engines, as sources of noise in the production departments. Influence of thickness sound-absorbing material can be supported by the values obtained for the absorption coefficient, but it can be studied as a study case in the anechoic chamber, where the sound pressure level is measured with a sound level meter. Cases captured: a free engine; the engine placed in a metallic cube and motor inserted; metal cube that was doubled separately with one material and then with the composite material proposed. For each situation are eight determinations on the perimeter of a circle with a radius of one meter from the source of the noise. Plot a graph of experimental results that support the idea: greater thickness of the layer of material will cause a better absorption of noise.

Research on the Vibration Measurement Approach to the On-Line Noise Evaluation for Vehicle Transmissions

2012 ◽  
Vol 562-564 ◽  
pp. 1163-1167
Author(s):  
Feng Qiang Zhao ◽  
Guang Qiang Li ◽  
Hong Ying Hu ◽  
Jia Lu Du ◽  
Chen Guo
Keyword(s):  
Sound Pressure Level ◽  
Production Line ◽  
Background Noise ◽  
Sound Pressure ◽  
Sound Level ◽  
Pressure Level ◽  
Vibration Measurement ◽  
Vehicle Transmissions ◽  
Quality Of Transmission ◽  
Level Meter

At present, the common method of testing noise generated by vehicle transmission before delivery is to measure the noise sound pressure level by means of sound level meter. Since the measurement result is susceptible to background noise, the method can only be operated in anechoic chamber. In this paper, in order to measure sound pressure level directly on production-line, a new vibration measurement method and its relevant formula are presented. The proposed method can effectively avoid being affected by background noise and obtain the sound pressure level of transmission noise on production-line by testing the vibration acceleration signals of transmission box. It’s proved that the new method makes the delivery test of transmission noise more convenient and effective. Moreover, it can improve the delivery quality of transmission as well as the performance of whole vehicle.

Test and Analysis of Noise Reduction Effect for Different Heights and Distances of Sound Barrier

2011 ◽  
Vol 243-249 ◽  
pp. 4447-4450 ◽  
Author(s):  
Yan Liu ◽  
Bing Yang ◽  
Xiao Pai Zhang ◽  
Zhi Fang Zhong ◽  
Hua Xin Dong ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Sound Pressure Level ◽  
High Frequency ◽  
Sound Pressure ◽  
Pressure Level ◽  
High Frequency Range ◽  
Frequency Range ◽  
Sound Barrier ◽  
Test Points ◽  
Reduction Effect

Based on the comparative analysis on the low-noise road surface, noise reduction green belts, noise barriers and other noise reduction methods, the sound barrier is put forward as an important method for reducing the city road traffic noise. The noise reduction effects for different heights and different distances of the sound barrier are tested and analyzed through noise and vibration test and analysis system, the following conclusions can be drawn. At the same heights from the ground, the father the test points away from the noise barrier, the higher the sound pressure level will be; At the same distances from the sound barrier, the nearer the test points from the ground, the smaller the sound pressure level will be; All of the sound pressure level curves have basically the same variation trend and the main noise frequency band is from 160 to 1600Hz; In the high frequency range which is greater than 1600Hz, the sound pressure level decrease significantly, indicating that the sound barrier has better noise reduction effect for high frequency range. The results provide the basis for the design of the sound barriers.

scholarly journals Acoustic and Flow Aspects of Novel Synthetic Jet Actuator

Actuators ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 100 ◽  
Author(s):  
Emil Smyk ◽  
Paweł Gil ◽  
Rafał Gałek ◽  
Łukasz Przeszłowski
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Optimal Solution ◽  
Sound Level ◽  
Pressure Level ◽  
Synthetic Jet ◽  
Acoustic Properties ◽  
Synthetic Jet Actuator ◽  
Flow Parameters ◽  
Level Meter

The acoustic and flow aspects of the novel synthetic jet actuator (SJA) with fins inside the cavity were experimentally investigated for three types of enclosure design and two models of loudspeaker. The aim of the study is to find the parameter which connects the flow and acoustic properties of the SJA and allows us to choose the optimal solution in those regards. The hot wire anemometry was used for the velocity measurements and the sound pressure level was measured with a sound level meter. The model of the loudspeaker turned out to have a significantly stronger impact on the flow parameters and noise level than the shape of the fins in the cavity. The parameter that showed a dependence on the shape of the fins was the actuator’s efficiency. A ratio of the root-mean-square velocity at the orifice axis to the sound pressure level (U0.c/SPL) was used to connect the acoustic and flow properties of the tested actuators. This parameter was subsequently applied to determine the best configuration among the tested actuators.

Audiological and noise exposure findings among members of a brazilian folklore music group

Work ◽  
2021 ◽  
pp. 1-7
Author(s):  
Carina Moreno Dias Carneiro Muniz ◽  
Sergio Fernando Saraiva da Silva ◽  
Rachel Costa Façanha ◽  
Daniela Bassi-Dibai ◽  
Fabricio Brito Silva ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Sound Pressure Level ◽  
High Frequency ◽  
Sound Pressure ◽  
Noise Exposure ◽  
Descriptive Study ◽  
Pressure Level ◽  
Noise Induced Hearing Loss ◽  
Loud Noise ◽  
Two Stages

BACKGROUND: Musicians and dancers can be considered an at-risk population for developing noise-induced hearing loss. OBJECTIVES: To determine the audiological profile of members of a folklore-related music group and quantify noise exposure at their rehearsal venue. METHODS: This was a quantitative and descriptive study. The musicians and dancers were evaluated in two stages: an interview about their working life, followed by high frequency tonal audiometry. The sound pressure level in the group’s rehearsal venue was measured using a BEK 2270 Noise Analyzer. RESULTS: A total of 7.2% of the subjects had noise-induced hearing loss (NIHL) and 39% of the audiometric tests were notch type. During the interview 31.7% of the subjects mentioned discomfort from loud noise, although none of them used ear protection. The environmental assessment showed inadequate humidity and oscillating temperature. Twenty sound pressure level measurements were performed for Leq (equivalent sound pressure levels) and the results ranged from 88 dB (A) to 99 dB (A) with a mean of 97.05. CONCLUSIONS: Exposure to high levels of sound pressure has led to NIHL in some members of the group. Some of those with normal hearing also presented a notch configuration characteristic of NIHL. Tinnitus, indicating that a change in hearing has occurred, was the most frequent auditory symptom.

scholarly journals The assessment of the sawmill noise

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
P. D’Antonio ◽  
C. D’Antonio ◽  
C. Evangelista ◽  
V. Doddato
Keyword(s):  
Data Processing ◽  
Sound Pressure Level ◽  
Noise Level ◽  
Sound Pressure ◽  
Sound Level ◽  
Pressure Level ◽  
Published Data ◽  
Noise Levels ◽  
Different Types ◽  
Level Meter

Noise is a serious and widespread problem in many workplaces like in sawmill. The published data for the year 2010 about the total number of pathologies from work in Italia due to the noise, showed 5222 cases divided by sex, in fact for females there are instances in number of 221 while the male has a number of cases is equal to 4961. The aim of this work was to detect the sound level caused by the use of the machineries in a sawmill. The measurements were carried out through an instrument known as noise level meter, equipped with a microphone and connected to a computer for data processing and analysis of variance to a factor in excel, and able to assess noise levels at any particular point in the mill. The machines were subjected in relief and with several different types of wood materials. Obviously, in our case a fundamental role takes the moisture of wood. The drying operation is intended to obtain that degree of humidity of the wood, generally it must be between 7 and 16%, compatible with the type of glue used and, above all, appropriate to the target structures. The machines that have the highest sound pressure levels were trimmer and profiler, with values ranging between 85 dB(A) and 110 dB(A). Finally, it’s possible conclude that the sound pressure level increases when the aspiration equipment is turned on, the noise of machinery decreases during the processing of wood and that, increasing the thickness, decreased the noise emitted by the machine.

scholarly journals THICKNESS INFLUENCE ON ABSORBING PROPERTIES OF STRATIFIED COMPOSITE MATERIALS

2016 ◽  
Vol 21 (4) ◽  
Author(s):  
IAȘNICU (STAMATE) IULIANA ◽  
VASILE OVIDIU ◽  
IATAN RADU
Keyword(s):  
Composite Material ◽  
Sound Pressure ◽  
Layered Composite ◽  
Sound Level ◽  
Pressure Level ◽  
Sound Level Meter ◽  
Absorbing Materials ◽  
Absorbing Material ◽  
Study Case ◽  
Level Meter

Plates known as sound absorbing materials: textiles recovered fabrics plus polyethylene are made layered composite material intended to be used to encapsulate industrial engines, as sources of noise in the production departments. Influence of thickness sound-absorbing material can be supported by the values obtained for the absorption coefficient, but it can be studied as a study case in the anechoic chamber, where the sound pressure level is measured with a sound level meter. Cases captured: a free engine; the engine placed in a metallic cube and motor inserted; metal cube that was doubled separately with one material and then with the composite material proposed. For each situation are eight determinations on the perimeter of a circle with a radius of one meter from the source of the noise. Plot a graph of experimental results that support the idea: greater thickness of the layer of material will cause a better absorption of noise.

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