Calculation of Reflections in an Urban Environment

Heutschi, Kurt

doi:10.3813/aaa.918193

Cited by 19 publications

(17 citation statements)

References 15 publications

(17 reference statements)

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“…They are different in each virtual sound environment and correspond to the traffic noise coming from the highway and received by a pedestrian while walking along the bridge at 3 m from its edge, of the FDTD technique, the calculation was limited to 2 dimensions, which is however suitable for a longitudinal geometry with a constant section like a bridge (Figure 2). In addition, a 2D to 3D correction was applied to account for differences in free field propagation for point and line sources (Heutschi, 2009). A perfectly reflective material was assigned to all surfaces, including the barriers.…”

Section: Auralizationmentioning

confidence: 99%

Using Virtual Reality for assessing the role of noise in the audio-visual design of an urban public space

Sánchez

Renterghem

sun

et al. 2017

Landscape and Urban Planning

137

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ABSTRACT:Sound planning is not often included in the urban design process despite the well-known audio-visual interactions of human perception. A methodology to compare the overall appreciation of future renovation alternatives of urban public spaces using Virtual Reality Technology is proposed. This method is applied to assess the role of noise in the overall appreciation of a walk on a bridge crossing a highway. The auralization is a dynamic 3D surround based on B-format recordings (ambisonics), filtered by means of full-wave numerical calculations obtaining the sound field behind noise barriers along the bridge's edge. Four different styles of visual street design including different noise barrier heights in combination with the 4 corresponding predicted sound fields were evaluated for their pleasantness by 71 normal-hearing participants on 4 separate days. Each day participants experienced all the visual environments with only one soundscape (to elude direct sound comparison) and anything related to sound was not mentioned in the first part of the experiment. Even in this non-focussed context, a statistically significant effect of the sound environment on the overall appreciation was found. In general, the pleasantness increases with traffic noise level reduction, but the visual design has a stronger impact. By mentioning the soundscape while introducing the evaluation, slightly lower (but statistically significantly different) pleasantness ratings were obtained. Instead of increasing noise barrier height, improving the visual design of a lower barrier seems more effective to increase pleasantness.Visual designs including vegetation strongly outperform others. The virtual experience was rated as immersive and realistic.3

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Section: Auralizationmentioning

confidence: 99%

Using Virtual Reality for assessing the role of noise in the audio-visual design of an urban public space

Sánchez

Renterghem

sun

et al. 2017

Landscape and Urban Planning

137

View full text Add to dashboard Cite

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“…A transformation from 2D to 3D should therefore be applied. As it is difficult to estimate the distance travelled by every wave reaching the receiver after multiple reflections in the canyon, Heutschi [35] suggested a transformation consisting of multiplying the time signal with 1/�( * ) where c is the sound speed and t the time. In this approach the time travelled by the wave is assumed proportional to the distance travelled.…”

Section: Experimental Validationmentioning

confidence: 99%

The effect of street canyon design on traffic noise exposure along roads

Sánchez

Renterghem

Thomas

et al. 2016

Building and Environment

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Abating road traffic noise pollution is one of the main urban environmental challenges nowadays.However, architects and urbanists take decisions on urban regulations that define the shape of streets and buildings without taking this aspect into account. Furthermore, there is little information about the influence of urban geometry on traffic noise exposure in streets. In this study, the effect of street canyon design on sound pressure level distribution is numerically studied in high detail with the full-wave finite-difference time-domain method (FDTD). The CNOSSOS equivalent source power spectra were used to approach road traffic noise sources along two traffic lanes. Receivers both along the façades and the sidewalks have been considered in 42 cases. Numerical results demonstrate that building shape, street geometry and the presence of street furniture can have a strong impact on people's noise exposure. Building shape can be responsible for variations of up to 7.0dB(A) at pedestrians. Building-façade design can reduce the average exposure at windows with 12.9dB(A). It was further predicted that street geometry can enhance the positive effect of low barriers to 11.3dB(A) along sidewalks. It was therefore concluded that carefully designing building façades and street geometry could improve the sound climate for people living and walking along busy urban streets and should be considered in future urban street design.

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“…Other outdoor sound propagation effects that may be relevant in certain situations are screening [37][38][39], foliage attenuation [38], meteorological effects due to an inhomogeneous atmosphere [38][39][40][41][42], as well as reflections at artificial [38,43] and natural surfaces [42,44,45]. Most published environmental noise auralization models simulate some of the above listed effects by applying a 1/3 octave filter bank and adjusting the filter gains [8,14,15].…”

Section: Propagation Filteringmentioning

confidence: 99%

Auralization of Accelerating Passenger Cars Using Spectral Modeling Synthesis

2015

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While the technique of auralization has been in use for quite some time in architectural acoustics, the application to environmental noise has been discovered only recently. With road traffic noise being the dominant noise source in most countries, particular interest lies in the synthesis of realistic pass-by sounds. This article describes an auralizator for pass-bys of accelerating passenger cars. The key element is a synthesizer that simulates the acoustical emission of different vehicles, driving on different surfaces, under different operating conditions. Audio signals for the emitted tire noise, as well as the propulsion noise are generated using spectral modeling synthesis, which gives complete control of the signal characteristics. The sound of propulsion is synthesized as a function of instantaneous engine speed, engine load and emission angle, whereas the sound of tires is created in dependence of vehicle speed and emission angle. The sound propagation is simulated by applying a series of time-variant digital filters. To obtain the corresponding steering parameters of the synthesizer, controlled experiments were carried out. The tire noise parameters were determined from coast-by measurements of passenger cars with idling engines. To obtain the propulsion noise parameters, measurements at different engine speeds, engine loads and emission angles were performed using a chassis dynamometer. The article shows how, from the measured data, the synthesizer parameters are calculated using audio signal processing.

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Calculation of Reflections in an Urban Environment

Cited by 19 publications

References 15 publications

Using Virtual Reality for assessing the role of noise in the audio-visual design of an urban public space

Using Virtual Reality for assessing the role of noise in the audio-visual design of an urban public space

The effect of street canyon design on traffic noise exposure along roads

Auralization of Accelerating Passenger Cars Using Spectral Modeling Synthesis

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