擬雙耳音質感測之研究

The Study of Sound Measurement Based on Binaural Technique

曾嘉豪(Chia-Haw Tzeng)

指導教授 ： 洪振發

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2012年)

https://doi.org/10.6342/NTU.2012.02499

摘要

隨著人對聽覺感受要求的提高，因而使影音產品對音質的要求提升，以單一麥克風進行錄音或是量測不足以表達人耳真實的聽覺感受。考量人類聽覺感受的生理與心理特性，模擬雙耳錄音技術逐漸被重視。在聽覺中，外耳形狀影響對音源方向具定位和濾波的效果，耳廓效應(Pinna Effect)顯示聲音在進入耳道之前，外耳的形狀提供了聲音繞射和反射空間，提供了具人體特色的濾波器功能；頭部效應提供聲音源的方向判斷，人耳與人頭給予了人在空間聲場中多樣的聽覺感受。
本研究考量人耳聽覺感受，應用雙耳量測技術，物理聲學原理及心理聲學參數中的響度概念為基準，設計出簡化擬外耳幾何構造，並利用有限元素與邊界元素法，進行頻率響應分析，歸納出初步形狀的設計原則與加權趨勢。更進一步於無響室的環境進行聲場量測實驗，並與仿真人偶進行比對。
實驗的頻率響應與仿真人偶數據對照結果驗證了與SYSNOISE中邊界元素模擬設定的互通性。在響度實驗上可以用簡化的仿人耳模型代替人頭和耳朵的組合，有基本的聲音來源方向判定功能，但在共振頻率上有過大的響應值。未來可朝幾何非對稱以及調整材質以追求有更吻合人耳響度的耳朵簡化模型。

關鍵字

雙耳技術 ； 心理聲學 ； 耳廓效應 ； 有限元素法 ； 邊界元素法

並列摘要

With the demand of sound quality, single microphone recording has limited ability to build the true auditory sensation. Therefore, taking the feature of human hearing into account, binaural measurement technique plays an important role in these days. The shape of external ear can detect the source and direction of sound wave, and the Pinna effect shows the reason that the behavior of reflection and diffraction of incident acoustic wave will occur before transmitting into the ear canal. Masking effect of head provide the ability of direction identification of sound source. Both provides diversity of hearing sense in acoustic field.
In this study, a simplified external ear geometry model based on binaural recording technology was designed. The characteristic of frequency response of fundamental ear like shape were investigated by means of finite element method and boundary element method. Moreover, two simplified external ear models were tested according to the frequency weighting method and the result was compared with Artifical Head in the Anechoic Chamber.
The experiment result of frequency response of simplified ear model comparing with head acoustic has good agreement with simulation results by SYSNOISE. The frequency response and BEM simulation agreed with measurement. The result shows that simplified out ear model could represent the head and ear system in the loudness experiment. The model has basic ability to do identification of sound direction, nevertheless, the frequency response at the resonance frequency is larger than measured result of head acoustic. The asymmetric geometry and different materials will be adapted for the simplified ear model in the future.

並列關鍵字

binaural technique ； psychoacoustic ； pinna effect ； FEM ； BEM

參考文獻

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