校正小型無響室用之標準音源的設計與噪音強度及指向性驗證

Design of the Reference Sound Source and Analysis of Its Sound Intensity and Directionality for Calibrating Miniature Anechoic Chambers

陳永樹 ； 林泱鉦 ； 涂聰賢 ； 蕭榮恩

《中華民國音響學刊》 15期 (2011/06) Pp. 63-82

https://doi.org/10.30049/JASRC.201106.0004

摘要

本研究設計一小型無響室校正用之標準音源(Reference Sound Source-RSS)。首先就產生音源之葉片角度與支撐結構等做相關設計，然後用Fluent軟體分析初始設計之音源周圍風速分佈與實驗結果做比對，據以做設計改善而進階分析製作出小型標準音源。並針對其最關鍵之噪音強度與指向性做鑑別，在100Hz~10kHz之間的聲壓值差均在標準規範之6dB內，但唯有單一頻率之2.5kHz其壓聲值差為6.9dB，因係極高頻範圍且誤差不大，故此設計之標準音源應可應用於小型無響室校正使用。

關鍵字

無響室 ； 指向性 ； 噪音強度 ； 標準音源

並列摘要

This study developed a new type of small reference sound source for the calibration of non-standard small anechoic or semi-anechoic chambers. It started with different designs in the blades and supporting structure of the noise generating device. The analysis with the Fluent software and experiment of wind speeds were conducted and compared with each other for the verification of the analysis model. The model was then used for the further design of a complete small reference sound source. Two critical design factors of the noise intensity and directionality were investigated later. The results showed that the sound pressure differences are all within 6 dB between 100 Hz~10 kHz following the ISO standards except that of 2.5 kHz which is 6.9 dB. This slight deviation at the solely high frequency is believed not affecting much on the newly developed reference sound source for the calibration of a small anechoic chamber.

並列關鍵字

anechoic ； directionality ； noise intensity ； reference sound source