An Experimental Study of the Performance of a Crossed Rib Diffuser in Room Acoustic Control
This paper presents a crossed rib diffuser (CRD) as an effective tool for room acoustic control. We performed an experimental investigation of its effectiveness using a specimen manufactured for this trial. The CRD is constructed by overlapping two one-dimensional (1D) periodic rib diffusers with di...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-04-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/11/9/3781 |
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| author | Takumi Yoshida Yasutaka Ueda Norimasa Mori Yumi Matano |
| author_facet | Takumi Yoshida Yasutaka Ueda Norimasa Mori Yumi Matano |
| author_sort | Takumi Yoshida |
| collection | DOAJ |
| description | This paper presents a crossed rib diffuser (CRD) as an effective tool for room acoustic control. We performed an experimental investigation of its effectiveness using a specimen manufactured for this trial. The CRD is constructed by overlapping two one-dimensional (1D) periodic rib diffusers with different specifications so that they are crossed at non-right angles. The CRD achieves a higher scattering coefficient than 1D periodic rib diffusers in a wide band while maintaining the simple and friendly design of 1D periodic rib diffusers applicable to various architectural spaces. Moreover, inserting an absorbing layer between upper and lower ribs of the CRD, (CRD-A) yields a high broadband absorption coefficient. We first evaluated the random-incidence scattering coefficient of CRD using a 1/5 scaled model in comparison with those of 1D periodic diffusers assessed with a numerical method. Then, absorption coefficients for the CRD and the CRD-A were measured using a reverberation room. Subsequently, an experiment on a small meeting room with a 1D periodic rib diffuser, the CRD and the CRD-A was conducted to present performance of the CRD in room acoustic control. Impulse response measurements and evaluations of reverberation parameters (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>T</mi><mn>20</mn></msub></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>E</mi><mi>D</mi><mi>T</mi></mrow></semantics></math></inline-formula>) and speech clarity (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>D</mi><mn>50</mn></msub></semantics></math></inline-formula>) were conducted. Additionally, we present differences in structure of reflected sounds found for the flat wall, the CRD and the CRD-A visually using a four-channel sound field microphone. |
| first_indexed | 2024-03-10T12:04:54Z |
| format | Article |
| id | doaj.art-9879157d67754be1bd82e6c300c12120 |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-10T12:04:54Z |
| publishDate | 2021-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-9879157d67754be1bd82e6c300c121202023-11-21T16:38:54ZengMDPI AGApplied Sciences2076-34172021-04-01119378110.3390/app11093781An Experimental Study of the Performance of a Crossed Rib Diffuser in Room Acoustic ControlTakumi Yoshida0Yasutaka Ueda1Norimasa Mori2Yumi Matano3Technical Research Institute, Hazama Ando Corporation, 515-1 Karima, Tsukuba-City 305-0822, JapanTechnical Research Institute, Hazama Ando Corporation, 515-1 Karima, Tsukuba-City 305-0822, JapanAcoustics Products Department, Daiken Corporation, 2-5-8 Kaigandori, Minami, Okayama 702-8045, JapanAcoustics Products Department, Daiken Corporation, 2-5-8 Kaigandori, Minami, Okayama 702-8045, JapanThis paper presents a crossed rib diffuser (CRD) as an effective tool for room acoustic control. We performed an experimental investigation of its effectiveness using a specimen manufactured for this trial. The CRD is constructed by overlapping two one-dimensional (1D) periodic rib diffusers with different specifications so that they are crossed at non-right angles. The CRD achieves a higher scattering coefficient than 1D periodic rib diffusers in a wide band while maintaining the simple and friendly design of 1D periodic rib diffusers applicable to various architectural spaces. Moreover, inserting an absorbing layer between upper and lower ribs of the CRD, (CRD-A) yields a high broadband absorption coefficient. We first evaluated the random-incidence scattering coefficient of CRD using a 1/5 scaled model in comparison with those of 1D periodic diffusers assessed with a numerical method. Then, absorption coefficients for the CRD and the CRD-A were measured using a reverberation room. Subsequently, an experiment on a small meeting room with a 1D periodic rib diffuser, the CRD and the CRD-A was conducted to present performance of the CRD in room acoustic control. Impulse response measurements and evaluations of reverberation parameters (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>T</mi><mn>20</mn></msub></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>E</mi><mi>D</mi><mi>T</mi></mrow></semantics></math></inline-formula>) and speech clarity (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>D</mi><mn>50</mn></msub></semantics></math></inline-formula>) were conducted. Additionally, we present differences in structure of reflected sounds found for the flat wall, the CRD and the CRD-A visually using a four-channel sound field microphone.https://www.mdpi.com/2076-3417/11/9/3781acoustic diffuserarchitectural acousticmeeting roomreverberationroom acoustic controlscattering coefficient |
| spellingShingle | Takumi Yoshida Yasutaka Ueda Norimasa Mori Yumi Matano An Experimental Study of the Performance of a Crossed Rib Diffuser in Room Acoustic Control Applied Sciences acoustic diffuser architectural acoustic meeting room reverberation room acoustic control scattering coefficient |
| title | An Experimental Study of the Performance of a Crossed Rib Diffuser in Room Acoustic Control |
| title_full | An Experimental Study of the Performance of a Crossed Rib Diffuser in Room Acoustic Control |
| title_fullStr | An Experimental Study of the Performance of a Crossed Rib Diffuser in Room Acoustic Control |
| title_full_unstemmed | An Experimental Study of the Performance of a Crossed Rib Diffuser in Room Acoustic Control |
| title_short | An Experimental Study of the Performance of a Crossed Rib Diffuser in Room Acoustic Control |
| title_sort | experimental study of the performance of a crossed rib diffuser in room acoustic control |
| topic | acoustic diffuser architectural acoustic meeting room reverberation room acoustic control scattering coefficient |
| url | https://www.mdpi.com/2076-3417/11/9/3781 |
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