竹質擴散板於不同序列之聲音散射性能研究

室內聲環境適切運用吸音與擴散裝修材可發揮最佳聆聽品質。選定永續效率高之竹材依天然構造製作竹管與半剖擴散板，對不同竹種、序列與管徑深度變化解析各頻帶最佳聲音散射特性。本研究以1、X、V型序列探討散射性能，結果竹能QRD擴散板較中空竹管擴散板可提昇10%以上之散射性能；而QRD竹節與中空竹管擴散板輔以隔板變化則以I型序列散射性圍最佳。故以I型變化設計為MLS序列，結果以孟宗竹與組合性（孟宗竹+桂竹）擴散板在MLS與I型序列中散射性能優於桂竹擴散板；且半剖弧面正反序列擴散板其竹節長度越短（17cm）散射性能越佳（較33cm者與67cm者佳），L=17與67（cm）於630Hz之差異量0.34為最大。半剖弧面正反序列擴散板選定竹管直徑10、5、3.5及2.5（cm）以隔板與間距為變因，結果顯示竹管擴散板隨著管徑越大其散射性能越佳。

關鍵字

竹質擴散板；散射性能；二次餘數擴散板（QRD）；最大長度序列（MLS）

並列摘要

Optimizing listening quality in an indoor acoustic environment requires the appropriate use of sound-absorption and diffusion materials. Diffusers made of bamboo tubes and split bamboo present an ecologically-sustainable choice, with differences in bamboo species, sequence, diameter and depth providing optimal diffusion for each frequency band. This study investigates the diffusion properties of I. X. and V-shaped sequences , and finds that the diffusion characteristics of bamboo QRD diffusers are significantly superior to that of hollow bamboo diffusers (＞10%). In addition, QRD bamboo and hollow bamboo diffusers offer optimal diffusion performance when I-type with flutter, Design changes to the MLS sequence resulted in a combination Moso and Makino bamboo diffuser on the MLS with an I-type sequence that demonstrated diffusion performance superior to that of the Makino bamboo diffuser. As the bamboo length of the half-arc positive and negative sequence diffuser was shorter (17cm's), the diffusion properties was better (better than 33cm's and 67cm's). L= 17 and 67(cm) showed the greatest difference at 630 Hz (0.34). Different diameters of the half-arc positive and negative sequence diffuser bamboo(10,5, 3.5 and 2,5 cm) served as the variable for distance and flutter. Results showed scattering performance improved as the diameter of the bamboo diffuser increased.