臺灣縣市政府大廳音響性能及耦合效應分析之研究

A Study on Acoustic Performances and Coupling Effect of Town Hall’s Lobbies in Taiwan

近年來，台灣縣市政府大廳的使用模式趨向於多目的使用，它不只是市府大樓內部動線的樞紐點，同時也扮演成演講、記者會、展覽、表演等場所，因此合適的公共建築大廳音環境設計是必須的。然而此類型的空間在設計時為了達到視覺效果，常常使用了反射性較高的材料，忽略了吸音材料的重要性。另外，大廳空間容易產生耦合效應，使餘響時間變長，導致大廳的音環境更加吵雜。本研究量測台灣10所縣市政府之公共建築大廳，探討餘響時間、早期衰減時間、背景噪音、語音清晰度及科合效應等因子，說明相關因子與室型、室內材料之關係，並以聲場模擬的方式探討耦合效應具有影響性的因子。研究結果發現，各縣市政府大廳的隔音度不足，容易受到交通噪音及機房噪音的影響，導致背景噪音過高；且大廳與耦合空間設置的吸音材明顯不足，餘響時間有過長的趨勢。在聲場模擬部分，分析了耦合空間型態、耦合開口面積及吸音材的設置等因子，並以模擬之實際大廳案例，提出了降低耦合效應之方法。

Lobbies are designed as multi purpose public spaces, and town hall lobbies act as bridge between the people and the government. Generally, lobbies are not only a key space for circulation but can also be a venue for musical performances. There is always a large amount of chatter in the lobby; therefore, a proper design for the acoustic environment is quite necessary. However, architects are usually concerned about the visual effect, and they often use designs made of hard materials with high sound ref1ection that lack sound absorptive material. Therefore, most town hall lobbies are quite noisy. This paper studied ten town hall lobbies in Taiwan, measuring their reverberation time (RT), early decay time (EDT), background noise (BGN), rapid speech transmission index (RASTI) and the coupling effect. The relationships among RT, EDT, BGN, RASTI, the room shape and the interior materials were also analyzed.