NOISE SHIELDING BY SIMPLE BARRIERS: COMPARISON BETWEEN THE PERFORMANCE OF SPHERICAL AND LINE SOUND SOURCES

2000 ◽  
Vol 08 (03) ◽  
pp. 495-502 ◽  
Author(s):  
D. OUIS
Keyword(s):  
Sound Source ◽  
Insertion Loss ◽  
Line Source ◽  
Wave Reflection ◽  
Noise Source ◽  
Sound Level ◽  
Sound Sources ◽  
Noise Shielding ◽  
Noise Barrier ◽  
Wave Incidence

This study is concerned with the theoretical solution to the problem of sound screening by simple hard barriers on the ground with special emphasis given to the type of wave incidence, namely a comparison between the use of either a spherical or a cylindrical sound source. For a receiver at the shadow of the noise source, the field may be assumed to be due to the edge wave and for this, exact solutions are used. Regarding the wave reflection on an impedance ground, exact formulations are also used, and finally, some calculations are made on the performance of a hard noise barrier on a two-impedance ground. As a conclusion, it is found that although the sound level at the receiver may show some small differences depending on the frequency and on the geometry of the problem, the overall insertion loss of the thin hard barrier is almost the same for the spherical and the line source, and the differences are found to amount to less than 1 dB for geometries of practical occurrence.

Analysis on Traffic Noise Attenuation by Using Sound Barrier

2014 ◽  
Vol 584-586 ◽  
pp. 776-779
Author(s):  
Xian Feng Huang ◽  
Chen Hui Zhu ◽  
Quan Shi
Keyword(s):  
Sound Source ◽  
Insertion Loss ◽  
Traffic Noise ◽  
Noise Attenuation ◽  
Noise Barriers ◽  
Sound Barrier ◽  
Noise Barrier ◽  
Significant Attenuation ◽  
Infinite Line ◽  
Insertion Losses

By applying noise insertion loss predicting model of the noise barriers, influencing factors on insertion loss of the sound barrier are investigated for achieving the significant attenuation effects. In term of the infinite line sound source and the finite length of the barriers, the sound insertion losses with varying parameters are calculated and compared. Finally, the meaningful results indicate that the economic and reasonable height and length of the noise barrier are gained to be beneficial for barrier design.

Active Reduction of Noise by Additional Noise Source and Its Limit

1989 ◽  
Vol 111 (4) ◽  
pp. 480-485 ◽  
Author(s):  
Ken’iti Kido ◽  
Hiroshi Kanai ◽  
Masato Abe
Keyword(s):  
Sound Source ◽  
Sound Pressure ◽  
Noise Control ◽  
Noise Source ◽  
Radiation Power ◽  
Active Noise Control ◽  
Primary Source ◽  
Dipole Source ◽  
Sound Sources ◽  
Effective Radiation

This paper describes further investigations of an active noise control system in which an additional sound source is set close to the primary (noise) source. Successful application of this method to duct noise control has already been reported (Kido, 1987). The synthesized sound radiated by the additional source is identical to that of the primary source, except in polarity. The additional and primary sources form a dipole sound source with reduced effective radiation power. In theory, the distance between these two sound sources should be much less than the shortest wavelength in the required frequency range to realize an ideal dipole source. Then, the total sound pressure would be expected to attenuate in proportion to the square of the distance from the center of the sources, and little sound power would be radiated. However, in practice, the distance cannot be set small enough, so there is only a relatively small area around the dipole where the sound pressure attenuates in proportion to the square of the distance. Further afield, it attenuates in direct proportion to distance. Noise reduction is therefore limited. This paper describes the effects and the limits of performance of such a system as a function of wavelength and the dimensions of sound sources.

The Influence of the Shape Space on the Scattering of the Sound Energy

2013 ◽  
Vol 855 ◽  
pp. 237-240
Author(s):  
Alena Pernišová ◽  
Dušan Dlhý
Keyword(s):  
Sound Source ◽  
Sound Propagation ◽  
Shape Space ◽  
Limited Range ◽  
Sound Level ◽  
Sound Sources ◽  
Sound Energy ◽  
Empty Area ◽  
The Way

The sound level adjacent to the sound sources is mainly characterized by the straight sound. The dispersion sound ratio is increasing with distance increasing and within the limited range round the sound source, the sound level is higher, in the area with dispersion bodies even higher than in an empty area. The laws of sound propagation in empty areas are derived on classical geometric base. The laws of sound propagation in large areas with dispersion objects are also derived from these laws complemented with the Kuttruff ́s equation of reverberation process in media with dispersion bodies. Simultaneously the sound energy is according to the purpose divided into the straight sound and the reverberation. The straight sound is the energetic ratio of sound, that is during the way to destination not dispersed and the propagation laws are equal to empty areas propagation laws are equal to empty areas propagation laws. The dispersed sound is the ratio of sound energy that reaches the destination after one or more reflections. The energy result is then the sum of densities of dispersion and straight sound.

Florida Noise Barrier Evaluation and Computer Model Validation

2003 ◽  
Vol 1859 (1) ◽  
pp. 72-78 ◽  
Author(s):  
Roger Wayson ◽  
John MacDonald ◽  
Ahmed EI-Assar ◽  
Win Lindeman ◽  
Mariano Berrios
Keyword(s):  
Insertion Loss ◽  
Traffic Noise ◽  
Sound Level ◽  
Noise Model ◽  
Barrier Method ◽  
Noise Barriers ◽  
Zone Length ◽  
Sound Levels ◽  
Noise Barrier ◽  
Source Level

The results of a project that investigated the effectiveness of in situ noise barriers in Florida are presented. The prediction accuracy of the FHWA Traffic Noise Model (TNM) is compared with STAMINA 2.0 and 2.1 (Florida-specific). A total of 20 barrier sites were visited during a 3-year period that resulted in 844 discrete 20-min equivalent sound level (Leq) measurements behind the barriers. Barrier insertion loss was determined using the ANSI indirect barrier method. A methodology was developed to estimate shadow zone length created behind highway noise barriers. All of the barriers tested were effective (>5 dB:LAeq insertion loss at distances equivalent to the first row of homes, where LAeq is the A-weighted Leq) except one site because of marginal additional shielding from a berm–barrier combination. Only three sites had an insertion loss of less than 5 dB at distances representative of the second row of homes. Overall, measurements indicate that the barriers provide substantial sound level reduction for residents along the highway. TNM was the best prediction model when considering all test sites; however, the STAMINA models were more accurate at predicting source level. TNM predictions using the Average pavement input overpredicted the reference sound levels measured at these sites. TNM predictions using the OGAC (open-graded asphalt concrete) input were improved (under 2 dB:LAeq of error) over those using the Average pavement type input. This result is expected because Florida uses an open-graded asphalt friction mix.

scholarly journals A study on the insertion loss of a noise barrier for a directional sound source.

1999 ◽  
Vol 20 (4) ◽  
pp. 325-328 ◽  
Author(s):  
Gensei Matsumoto ◽  
Kyoji Fujiwara ◽  
Akira Omoto
Keyword(s):  
Sound Source ◽  
Insertion Loss ◽  
Noise Barrier

scholarly journals Investigation for insertion loss of noise barrier for sound source moving at high speed

2003 ◽  
Vol 24 (3) ◽  
pp. 148-150 ◽  
Author(s):  
Seigo Ogata ◽  
Hideo Tsuru ◽  
Hirofumi Nakajima ◽  
Kyoji Fujiwara
Keyword(s):  
Sound Source ◽  
Insertion Loss ◽  
High Speed ◽  
Noise Barrier

Role of pinnae and head movements in localizing pure tones 1The authors would like to thank Mr. Remi Humbert for implementing the experiment in Turbo Pascal and for his further assistance.

1999 ◽  
Vol 58 (3) ◽  
pp. 170-179 ◽  
Author(s):  
Barbara S. Muller ◽  
Pierre Bovet
Keyword(s):  
Sound Source ◽  
Head Movement ◽  
Movement Analysis ◽  
Head Movements ◽  
Sound Sources ◽  
Localization Accuracy ◽  
Sound Effects ◽  
Posterior Quadrant ◽  
Localization Performance ◽  
Pure Tones

Twelve blindfolded subjects localized two different pure tones, randomly played by eight sound sources in the horizontal plane. Either subjects could get information supplied by their pinnae (external ear) and their head movements or not. We found that pinnae, as well as head movements, had a marked influence on auditory localization performance with this type of sound. Effects of pinnae and head movements seemed to be additive; the absence of one or the other factor provoked the same loss of localization accuracy and even much the same error pattern. Head movement analysis showed that subjects turn their face towards the emitting sound source, except for sources exactly in the front or exactly in the rear, which are identified by turning the head to both sides. The head movement amplitude increased smoothly as the sound source moved from the anterior to the posterior quadrant.

scholarly journals Towards Robust Multiple Blind Source Localization Using Source Separation and Beamforming

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 532
Author(s):  
Henglin Pu ◽  
Chao Cai ◽  
Menglan Hu ◽  
Tianping Deng ◽  
Rong Zheng ◽  
...  
Keyword(s):  
Source Localization ◽  
Sound Source ◽  
Indoor Localization ◽  
Weighting Function ◽  
Signal To Noise Ratio ◽  
Source Separation ◽  
Sound Source Localization ◽  
Angle Of Arrival ◽  
Sound Sources ◽  
Localization Algorithms

Multiple blind sound source localization is the key technology for a myriad of applications such as robotic navigation and indoor localization. However, existing solutions can only locate a few sound sources simultaneously due to the limitation imposed by the number of microphones in an array. To this end, this paper proposes a novel multiple blind sound source localization algorithms using Source seParation and BeamForming (SPBF). Our algorithm overcomes the limitations of existing solutions and can locate more blind sources than the number of microphones in an array. Specifically, we propose a novel microphone layout, enabling salient multiple source separation while still preserving their arrival time information. After then, we perform source localization via beamforming using each demixed source. Such a design allows minimizing mutual interference from different sound sources, thereby enabling finer AoA estimation. To further enhance localization performance, we design a new spectral weighting function that can enhance the signal-to-noise-ratio, allowing a relatively narrow beam and thus finer angle of arrival estimation. Simulation experiments under typical indoor situations demonstrate a maximum of only 4∘ even under up to 14 sources.

scholarly journals The optimum orientation of an absorbing barrier

2005 ◽  
Vol 461 (2060) ◽  
pp. 2369-2383 ◽  
Author(s):  
A.D Rawlins
Keyword(s):  
Noise Level ◽  
Noise Source ◽  
Shadow Region ◽  
Source Position ◽  
Absorbent Material ◽  
Noise Barrier ◽  
Receiver Point

In the following work, we solve the problem of the best orientation of a rigid noise barrier, which has one face lined with absorbent material, between a noise source and a receiver point in the shadow region of the barrier. By the ‘best orientation’, we mean that positioning of the barrier which yields the least noise level at the receiving point for a given barrier and source position.

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