擴散板之音響散射性能對小型聆聽空間聲場之影響

Effects of Wooden Diffusers on the Small Listening Room

室內裝修材料之聲音散射性能是室內音響設計的重要影響因子。裝修材料表面良好的散射性能有助音能量在空間分佈的一致性進而改善音響品質。本研究於迴響室進行隨機入射散射係數實驗分析，探討不同木質裝修材料於不同序列對聲音散射性能之影響。實驗結果顯示各式擴散版（闊葉材、針葉材、合板、中密度纖維板－MDF、孟宗竹、熱處理材）皆以有隔板（QRD）較無隔板於高頻（315 5k Hz）平均至少皆可提高10%以上之散射性能；其中以有隔板之MDF擴散板在1k、1.25k Hz可高於無隔板擴散板20%之散射性能，且六種材料擴散板以有隔板呈現其散射性能最佳（P<0.05）；本實驗結果可作為室內音響性能設計之參考依據。再者，擴散板置入空間後按不同裝修率比對實測與電腦模擬有正相關性後（R2=0.80），再以客觀因素（迴響時間與清晰度等）評估電腦模擬與實際童測之差異性。發現若以60%裝修率可有效降低迴響時間（630 5k Hz之迴響時間降至1秒內）、且裝修率低到40%也可獲得具良好清晰度（+1 +2dB）。

The sound-scattering performance of wooden interior decoration material is an important influential factor that dominate indoor sound design. Good sound-scattering performance help the consistent spatial distribution of sound energy and improves sound quality. The study doe the experiment with the sound- scattering performance of wooden interior decoration material in the Reverberation lab. To analyze the different type of wood n material and sequences. Experimental result for diffusers made of six different materials ( Hardwood、Softwood、plywood、Medium density fiberboard, MDF、Moso bamboo、Heat-treated Wood ) , supplemented by QRD prime structure variable, are found to improve average high frequency ( 3 15-5k Hz ) scattering performance by more than 10%, with MDF diffusers of 1k, 1.25k Hz providing optimal scattering at 20% above average, resulting in the scattering performance of the various material improving through the QRD sequence ( P<0.05 ) . The experimental results presented here can be used as a reference for indoor acoustic performance. In the second stage, a diffuser placed in an empty room to determine a positive correlation between the test and computer simulation (R2=0.80). The simulation' input parameters were then used to objectively evaluate (reverberation time & clarity) the difference between the computer simulation and the actual room. Results showed a 60% increase in the decoration rate effectively reduced reverberation time (630 to 5k Hz, the RT is reduced to 1 sec.), while a decoration rate below 40% could also maintain a good degree of clarity.