Effects of Reverberation and Sound Source to Auditory Localization in an Indoor Sound Field

• Main Authors: Hsin-Fu Chen, 陳信富
• Other Authors: Chiung-Yao Chen
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/3x4ybu

碩士 === 朝陽科技大學 === 建築及都市設計研究所 === 94 === As far as the investigation on the influence of reverberation time has on the discretion of sound source direction is concerned, M. Morimoto (1989) had long applied the method of bilateral cues of both reverberation energy (RT60 = 0.3, 0.9 sec.) and first reflection energy (delay time = 80, 160ms) in his exploration on its impact on the discretion of auditory spatial perception. In his findings, he had found among these influences that reverberation energy may be treated as the first reflection energy in his choosing of experimental subject, provided it was limited to Wolfgang Amadeus Mozart’s Symphony No. 41, Movement IV. M. Morimoto (1989) reasoned that human’s auditory spatial perception of reverberation changes with the changing of speech samples. (Chen & Xu , 2005 ) As such, by choosing different music samples to conduct experimental analysis, this study intends to explore whether spatial perception of sound source varies significantly with changing music motifs. According to the sound field design theory described by Yoichi Ando (1980), the determining factor of an ideal reverberation time length lies in the effective delay of autocorrelation function ( e). With this in mind, the researcher chose to conduct his experiment with simulated sound field in the lab where three speech samples: Sample A (Royal Pavane by Gibbon, e = 127 ms), Sample B (Sinfonietta, Opus 48; Ⅲ movement; Allegro con brio by Arnold, e = 35 ms) and Sample C (speech, female, e = 23ms) were adopted. Reverberation time was set at three time lengths: short (0.3 sec.), medium (0.9 sec.) and long (2.0 sec.) and then matched with the aforesaid three time lengths by using random numbers respectively. Directional angels responded by experimenters were scored according to the normal distribution, and ANOVA was then applied to conduct analysis and reviewing. Result showed that Motif A hit the highest accuracy level, while speech hit the lowest (p<0.01). The primary cause for this was the different e, that is, different motif compositions had resulted in the significant difference of discretion, verifying that the change of motifs will have an influence on human’s auditory spatial perception of sound source. Furthermore, in the respect of reverberation time, no difference of spatial perception influence was gained directly form here (p>0.05).