scholarly journals The difference between several methods of sound power level for determining the sound energy emitted by a sound source

2020 ◽  
Vol 1568 ◽  
pp. 012008
Author(s):  
B Purwanto ◽  
M Sabrina ◽  
D Rusjadi
Keyword(s):  
Sound Source ◽  
Power Level ◽  
Sound Power ◽  
Sound Energy ◽  
Sound Power Level ◽  
The Difference

Round-robin testing on Sound power level measurement for Reference Sound Source and Office printer

2021 ◽  
Vol 263 (6) ◽  
pp. 929-935
Author(s):  
Kohei Shimoda
Keyword(s):  
Standard Deviation ◽  
Sound Source ◽  
Power Level ◽  
Round Robin ◽  
Sound Power ◽  
Sample Standard Deviation ◽  
Sound Power Level ◽  
Two Samples ◽  
Standard Deviations ◽  
Better Than

Round-robin testing for two samples, Reference Sound Source in accordance with ISO 6926 and Office printer with electrophotographic engine, were executed by seven testing laboratories in Japan on 2020. All tests were executed with parallelepiped measurement surface in hemi anechoic chamber in accordance with testing standard for engineering-grade sound power determination, ISO 3744:2010. The results show that sample standard deviation for RSS is better than printer. Standard deviations for overall A-weighted sound power level for two samples are better than combined standard uncertainties calculated with reference example of standard deviations in ISO 3744 (1.5 dB for Reference Sound Source as standard deviation of operating/mounting condition is negligibly small, 1.6 dB for printer as stable operating/mounting condition 0.5 dB). This paper also indicates tips for those who would conduct round-robin testing to obtain valid results by obviating incorrect operations and malfunctions of printers or similar equipment from the experience of some round-robin tests.

Measurement and Assessment on Environmental Noise Impact of Electric Vehicles in Accelerating Condition

2021 ◽  
Vol 263 (2) ◽  
pp. 4199-4210
Author(s):  
Katsuya Yamauchi ◽  
Jo Yoshino
Keyword(s):  
Electric Vehicles ◽  
Combustion Engine ◽  
Power Level ◽  
Environmental Noise ◽  
Sound Power ◽  
Vehicle Speed ◽  
Noise Emission ◽  
Sound Power Level ◽  
Noise Impact ◽  
The Difference

Noise emission from the vehicles propelled by electric system (such as pure electric and hybrid electric vehicles, EVs) is usually lower than the conventional internal combustion engine vehicles. Some previous studies have been shown the difference in A-weighted sound power level of EVs from the conventional ones. The difference is not dramatically large, i.e. less than 4 dB when the cars running at constant speed of 20 km/h. In this paper, we present the additional measurement results of sound power level of EVs in accelerating condition. Because when the cars in accelerating condition, the difference of propulsion systems becomes more significant on noise emission. The results are shown as regression model of sound power level depending on the vehicle speed. Moreover, the environmental noise impact of growing population of EVs is assessed through a prediction of at a case of intersection.

REMOVED: Investigating the sound power level of a simplified underwater vehicle induced by flow separation

2020 ◽  
Vol 204 ◽  
pp. 107286
Author(s):  
Deng Rui ◽  
Zhang Zezhen ◽  
Pang Fuzhen ◽  
Wu Tiecheng ◽  
Luo Wanzhen
Keyword(s):  
Flow Separation ◽  
Power Level ◽  
Underwater Vehicle ◽  
Sound Power ◽  
Sound Power Level

scholarly journals A Comparison of Vibroacoustic Response of Isotropic Plate with Attached Discrete Patches and Point Masses Having Different Thickness Variation with Different Taper Ratios

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Bipin Kumar ◽  
Vinayak Ranjan ◽  
Mohammad Sikandar Azam ◽  
Piyush Pratap Singh ◽  
Pawan Mishra ◽  
...  
Keyword(s):  
Power Level ◽  
Low Frequency ◽  
Sound Radiation ◽  
Radiation Efficiency ◽  
Thickness Variation ◽  
Sound Power ◽  
Sound Power Level ◽  
Radiation Behavior ◽  
Thickness Variations ◽  
Different Thickness

A comparison of sound radiation behavior of plate in air medium with attached discrete patches/point masses having different thickness variations with different taper ratio of 0.3, 0.6, and 0.9 is analysed. Finite element method is used to find the vibration characteristics while Rayleigh integral is used to predict the sound radiation characteristics. Minimum peak sound power level obtained is at a taper ratio of 0.6 with parabolic increasing-decreasing thickness variation for plate with four discrete patches. At higher taper ratio, linearly increasing-decreasing thickness variation is another alternative for minimum peak sound power level suppression with discrete patches. It is found that, in low frequency range, average radiation efficiency remains almost the same, but near first peak, four patches or four point masses cause increase in average radiation efficiency; that is, redistribution of point masses/patches does have effect on average radiation efficiency at a given taper ratio.

scholarly journals A simulation of traffic noise emissions at a roundabout based on a cellular automaton model

Acta Acustica ◽  
2021 ◽  
Vol 5 ◽  
pp. 42
Author(s):  
Canyi Du ◽  
Xinfa Qiu ◽  
Feng Li ◽  
Ming Cai
Keyword(s):  
Cellular Automaton ◽  
Road Traffic ◽  
Power Level ◽  
Traffic Noise ◽  
Traffic Volume ◽  
Sound Power ◽  
Noise Emission ◽  
Urban Road ◽  
Speed Distribution ◽  
Sound Power Level

The calculation and evaluation of traffic noise is an important task in urban road design. Roundabouts are a common form of urban road intersection. The complexity of traffic operations makes the calculation of traffic noise near a roundabout challenging. To explore traffic noise at roundabouts, a cellular automaton traffic flow model for a two-lane roundabout is established. Based on this model, a dynamic simulation method for traffic noise at roundabouts is proposed. The traffic operation and noise emissions at a roundabout are simulated. The vehicle speed distribution and traffic noise distribution at the roundabout are analysed, and the relationship between the traffic volume and sound power level of the cells is discussed. Finally, the proposed method is compared with existing traffic noise models, and the accuracy and efficiency of the proposed method are verified. The results of this paper show that the speed distribution and noise emission distribution at the roundabout are not uniform. When the traffic volume increases to saturation, the noise emission on the ring road will not keep increasing, and the sound power level of the cells on the inner ring is approximately 2 dBA higher than that of the outer ring. The methods and results in this paper may be valuable for road traffic design and noise control.

Sound Radiation Characteristics of Lightweight Roof Constructions Excited by Rain

1994 ◽  
Vol 1 (4) ◽  
pp. 249-270 ◽  
Author(s):  
Hiromi Suga ◽  
Hideki Tachibana
Keyword(s):  
Transmission Loss ◽  
Power Level ◽  
Sound Radiation ◽  
Sound Intensity ◽  
Sound Power ◽  
Radiation Characteristics ◽  
Natural Rainfall ◽  
Artificial Rainfall ◽  
Sound Power Level ◽  
Measurement Results

In order to investigate the sound radiation characteristics of lightweight roof constructions when excited by rainfall, an artificial rainfall apparatus was constructed to simulate natural rainfall conditions. From the measurement results, it can be seen that the facility developed is practically applicable for the examination of the sound radiation characteristics of rain noise. It was therefore used in the measurement of sound power of 20 lightweight roofs. In addition, the relationship between sound power level and sound transmission loss measured by the sound intensity method was investigated statistically. As a result, it has been shown that a linear relationship exists between them and there is a possibility of estimating the sound power level from the transmission loss.

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