The strength of a steady sound field in a hall depends on the direct sound levcl and the level of reflections from all boundaries. But for speech and music having impulsive characteristics, only the direct sound and the early reflections are effectivc to the perceived loudness to the listener according to the integrating abili ty of the ear. Therefore, a series of subjective comparison tests are carried out in an anechoic room, using recorded "dry" speech as testing material are thus con ducted to investigate the contribution of short delayed echoes (early reflections) to thc loudness evaluation. Sound field consisting of primary sound and delayed echoes, single or multiple, are produced by electroacoustic means. Results show that the perceived louopess of the sound field is the function of the echo energy,angle of echo incidence and its temporal distribution. The law of the addition of energy to the echoes with a short delay is not applicable to multiple echoes as well as to a single echo after an interval exceeding 30-50 ms. In certain cases, they are much less than to be expected according to the said law.
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机译:如何发展银行品牌形象-以专注于财富管理业务的远东国际商业银行为例 =The Study of the Development of Bank’s Brand Image- A Case Study of Far Eastern Int’l Bank Targeting on Wealth Management
机译:materialmodell没有。 72 foer Betong:Erfarenheter fran en Experimentell och Numberisk studie(material modell no.72 for concrete-Experience from a Experimental and Numerical study)。