Computationally-efficient rendering of diffuse reflections for geometrical acoustics based room simulation
Geometrical acoustics is well suited for real-time room acoustics simulation and is often implemented using the image source model (ISM). One drawback of the ISM is its limitation to specular reflections, while sound scattering plays an important role in real environments. Here, computationally-effi...
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EDP Sciences
2025-01-01
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| Series: | Acta Acustica |
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| Online Access: | https://acta-acustica.edpsciences.org/articles/aacus/full_html/2025/01/aacus240021/aacus240021.html |
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| author | Ewert Stephan D. Gößling Nico Buttler Oliver van de Par Steven Hu Hongmei |
| author_facet | Ewert Stephan D. Gößling Nico Buttler Oliver van de Par Steven Hu Hongmei |
| author_sort | Ewert Stephan D. |
| collection | DOAJ |
| description | Geometrical acoustics is well suited for real-time room acoustics simulation and is often implemented using the image source model (ISM). One drawback of the ISM is its limitation to specular reflections, while sound scattering plays an important role in real environments. Here, computationally-efficient, digital-filter approximations are proposed to account for effects of non-specular scattered reflections in the ISM. For scattering at large surfaces such as room boundaries, each reflection is energetically split into a specular and a scattered part, based on the scattering coefficient. The scattered sound is coupled into a diffuse reverberation model. Temporal effects of the underlying surface scattering for an infinite ideal diffuse (Lambertian) reflector are derived and the resulting monotonic decay is simulated using cascaded all-pass filters. Effects of scattering and multiple (inter-) reflections caused by larger geometric structures at walls, and by objects in the room are accounted for in a highly simplified manner. A single parameter is used to quantify deviations from an empty shoebox room. The cumulated temporal effect of scattering along a reflection path is mimicked using cascaded all-pass filters adjusted to obtain a gamma-distribution-shaped envelope. The proposed method was perceptually evaluated with both music and pulse stimuli against dummy head recordings of real rooms. The results show a better agreement between the recording and the simulation for transient stimuli. In a technical evaluation, the temporal evolution of echo density showed a comparable profile for the suggested method and real rooms. |
| format | Article |
| id | doaj-art-748d7b9ab6f34923a6e67cf303813135 |
| institution | Kabale University |
| issn | 2681-4617 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | EDP Sciences |
| record_format | Article |
| series | Acta Acustica |
| spelling | doaj-art-748d7b9ab6f34923a6e67cf3038131352025-02-05T10:39:20ZengEDP SciencesActa Acustica2681-46172025-01-019910.1051/aacus/2024062aacus240021Computationally-efficient rendering of diffuse reflections for geometrical acoustics based room simulationEwert Stephan D.0https://orcid.org/0000-0002-1644-4947Gößling Nico1Buttler Oliver2van de Par Steven3Hu Hongmei4https://orcid.org/0000-0002-6103-4760Medizinische Physik and Cluster of Excellence “Hearing4all”, Carl von Ossietzky Universität OldenburgMedizinische Physik and Cluster of Excellence “Hearing4all”, Carl von Ossietzky Universität OldenburgMedizinische Physik and Cluster of Excellence “Hearing4all”, Carl von Ossietzky Universität OldenburgAkustik and Cluster of Excellence “Hearing4all”, Carl von Ossietzky Universität OldenburgMedizinische Physik and Cluster of Excellence “Hearing4all”, Carl von Ossietzky Universität OldenburgGeometrical acoustics is well suited for real-time room acoustics simulation and is often implemented using the image source model (ISM). One drawback of the ISM is its limitation to specular reflections, while sound scattering plays an important role in real environments. Here, computationally-efficient, digital-filter approximations are proposed to account for effects of non-specular scattered reflections in the ISM. For scattering at large surfaces such as room boundaries, each reflection is energetically split into a specular and a scattered part, based on the scattering coefficient. The scattered sound is coupled into a diffuse reverberation model. Temporal effects of the underlying surface scattering for an infinite ideal diffuse (Lambertian) reflector are derived and the resulting monotonic decay is simulated using cascaded all-pass filters. Effects of scattering and multiple (inter-) reflections caused by larger geometric structures at walls, and by objects in the room are accounted for in a highly simplified manner. A single parameter is used to quantify deviations from an empty shoebox room. The cumulated temporal effect of scattering along a reflection path is mimicked using cascaded all-pass filters adjusted to obtain a gamma-distribution-shaped envelope. The proposed method was perceptually evaluated with both music and pulse stimuli against dummy head recordings of real rooms. The results show a better agreement between the recording and the simulation for transient stimuli. In a technical evaluation, the temporal evolution of echo density showed a comparable profile for the suggested method and real rooms.https://acta-acustica.edpsciences.org/articles/aacus/full_html/2025/01/aacus240021/aacus240021.htmlscatteringvirtual acousticsgeometrical acousticsdigital filtersdiffraction |
| spellingShingle | Ewert Stephan D. Gößling Nico Buttler Oliver van de Par Steven Hu Hongmei Computationally-efficient rendering of diffuse reflections for geometrical acoustics based room simulation Acta Acustica scattering virtual acoustics geometrical acoustics digital filters diffraction |
| title | Computationally-efficient rendering of diffuse reflections for geometrical acoustics based room simulation |
| title_full | Computationally-efficient rendering of diffuse reflections for geometrical acoustics based room simulation |
| title_fullStr | Computationally-efficient rendering of diffuse reflections for geometrical acoustics based room simulation |
| title_full_unstemmed | Computationally-efficient rendering of diffuse reflections for geometrical acoustics based room simulation |
| title_short | Computationally-efficient rendering of diffuse reflections for geometrical acoustics based room simulation |
| title_sort | computationally efficient rendering of diffuse reflections for geometrical acoustics based room simulation |
| topic | scattering virtual acoustics geometrical acoustics digital filters diffraction |
| url | https://acta-acustica.edpsciences.org/articles/aacus/full_html/2025/01/aacus240021/aacus240021.html |
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