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Acoustics, Dynamics, and Controls

Scattering and Diffusion in Room Acoustics

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Full-Text Articles in Architecture

Scattered Responses From Suspended Reflector Panels With Rounded Edges, Jonathan Rathsam, Lily M. Wang Jun 2014

Scattered Responses From Suspended Reflector Panels With Rounded Edges, Jonathan Rathsam, Lily M. Wang

Lily M Wang

Sound reflections from most finite surfaces, such as overhead reflector panels, include a component known as edge diffraction. Edge diffraction is the scattered energy required to maintain a continuous sound field despite the discontinuity in acoustical impedance presented by the scatterer. Edge diffraction can interfere with primary scattered energy to produce comb filtering at receiver locations. Several decades ago, the effect of changing the edge profile of loudspeaker boxes was investigated with the goal of producing a smoother frequency response. By rounding the edges of loudspeaker boxes, the edge diffraction could be decreased noticeably [H. F. Olson, J. Aud. Eng. …


Scattered Responses From Suspended Reflector Panels With Rounded Edges, Jonathan Rathsam, Lily M. Wang Jun 2014

Scattered Responses From Suspended Reflector Panels With Rounded Edges, Jonathan Rathsam, Lily M. Wang

Lily M Wang

Sound reflections from most finite surfaces, such as overhead reflector panels, include a component known as edge diffraction. Edge diffraction is the scattered energy required to maintain a continuous sound field despite the discontinuity in acoustical impedance presented by the scatterer. Edge diffraction can interfere with primary scattered energy to produce comb filtering at receiver locations. Several decades ago, the effect of changing the edge profile of loudspeaker boxes was investigated with the goal of producing a smoother frequency response. By rounding the edges of loudspeaker boxes, the edge diffraction could be decreased noticeably [H. F. Olson, J. Aud. Eng. …


Reflector Responses: A Comparison Between Odeon’S Modified Ray Tracing Algorithm And A Filtered Boundary Element Method Model, Jonathan Rathsam, Lily M. Wang, Jens Holger Rindel, Claus Lynge Christensen Jun 2014

Reflector Responses: A Comparison Between Odeon’S Modified Ray Tracing Algorithm And A Filtered Boundary Element Method Model, Jonathan Rathsam, Lily M. Wang, Jens Holger Rindel, Claus Lynge Christensen

Lily M Wang

The biggest challenge for geometrical room acoustic computer models is to capture complex wave phenomena while maintaining the low computational load of the ray tracing algorithm. Special corrections must be added to the ray tracing algorithm to account for wave phenomena such as edge diffraction, which are ignored by classical geometrical acoustics. ODEON, a well-known geometrical computer model, is in the process of upgrading its ray tracing and scattering algorithm. The new algorithm allows users to specify transmission through reflector panel arrays. To aid in the development of ODEON’s new algorithm, its predictions are compared with predictions from a boundary …


A Review Of Diffuse Reflections In Architectural Acoustics, Jonathan Rathsam, Lily M. Wang Jun 2014

A Review Of Diffuse Reflections In Architectural Acoustics, Jonathan Rathsam, Lily M. Wang

Lily M Wang

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.