A Review of Diffuse Reflections in Architectural Acoustics

Abstract

Diffuse reflections have received increasing attention in architectural acoustics over the past quarter century. The term diffuse refers to non-specular directions. This paper identifies three mechanisms that cause diffuse reflections. Practitioners have found that changing specular reflections into diffuse reflections can reduce noise and echoes both indoors and outdoors. Developers of acoustical modeling software have also found that modeling diffuse in additional to specular reflections produces more accurate predictions. The final portion of this paper presents results for a study of scattering coefficients in acoustical modeling software.

Analysis of Residential Façade Patterns from Acoustic Viewpoint

“…Diffusers can be used on balcony fronts to reduce the noise reflected back down to the street [9], like vertical garden elements in balcony fronts, as an aesthetically appealing visual and pollutant filter between dwelling occupants and the street, see Figure 3. As well, absorbers can be located on balcony soffits lined with acoustic panels to absorb sound and reduce sound reflection back into the dwelling, see Figure 4.…”

Effect of 3D-Printed PLA Structure on Sound Reflection Properties

“…Acoustic design with good sound distribution is crucial in the internal spaces of such buildings [ 1 , 2 , 3 ]. In contrast to concert halls, in which the best possible sound acoustics are needed, in the case of main roads and other places, where there is high noise pollution, the aim is to absorb or effectively reflect noise, thus preventing the further propagation of sound waves [ 4 ]. However, other rooms which are used every day, such as classrooms, auditoriums, offices, or production halls, also require well-projected sound properties.…”

“…The former is when the reflection appears at the same angle at which it strikes the surface, like the reflection of light from a mirror. In contrast, diffuse reflection occurs when the sound energy is scattered in non-specular directions [ 4 ]. The direction of wave propagation is perpendicular to the front formed by all the Huygens’ wavelets.…”