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Belting, a vocal technique typically cultivated in musical theatre singing, differs timbrally from operatic singing in many interesting respects. The underlying phonatory differences have not been previously investigated in detail. Yet, belting is frequently associated with disturbances of voice function. Articulatory and phonatory characteristics are investigated in a female subject who is a professional singer (co-author JL) trained in both the operatic and belting styles and in an intermediate vocal technique (“mixed”). This article presents data obtained from this subject by video-fiberoptic observation of the pharynx, inverse filtering of airflow, and measurement of subglottal pressure. The results reveal that belting was characterized by very high subglottal pressures and sound levels, and apparently also by a comparatively high degree of glottal adduction. Comparisons with other investigations of related aspects of belting and operatic singing support the assumption that the data obtained from our subject are representative for these vocal techniques. 相似文献
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A Supercoherent State and a New Inhomogeneous Differential Realization of the SPL(2,1) Superalgebra 总被引:1,自引:0,他引:1
The supercoherent state of the SPL(2,1) superalgebra is constructed and its properties are discussed in detail. The new inhomogeneous differential realizations of the SPL(2,1) superalgebra are obtained. 相似文献
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论述了线阵列扬声器系统的定义,回顾了线阵列扬声器系统的发展历史,介绍了几种扬声器阵列如烛形线阵列、Bessel阵列等,总结归纳了线阵列扬声器系统设计的8个要点,它是对线阵列扬声器系统的基本认识和判断,供读者参考. 相似文献
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Phonation threshold pressure has been defined as the minimum subglottalpressure to generate phonation. Previous research has indicated that children may habitually employ higher subglottal pressures than adults. In the present investigation sound pressure level (SPL) and subglottal pressures at different pitch levels were measured at and above phonation threshold in nine children. Phonation threshold values were scattered in reasonable agreement with Titzes' prediction, although a discrepancy was noted regarding the frequency dependence in some voices. At normal conversational loudness and loudest level of phonation the children's PS values were between two to four and four to eight times the predicted threshold values, respectively. At normal conversational loudness and habitual pitch subglottal pressures were lower than those previously observed for children, but similar to those found for female adults. The SPL in softest and loudest phonation were somewhat lower as compared to previous phonetogram data for children and for female adults. At normal loudness and habitual pitch the SPL values were similar to those of female adults. For a doubling of Ps mean SPL increased by 10.5 dB on the average. 相似文献
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乘用车的车内声学性能直接影响人的主观感受,但仅靠主观评价来判定是不够的;必须通过引入有力的客观参量来刻画车内听觉的舒适度效果。而如何来设计车内噪声试验方案来诊断和改善声学水平则成了一个重要的环节。在乘用车车内噪声品质的开发过程中,综合应用语音清晰度和平均混响时间两个指标对车内吸声性能进行了对比分析。通过对实车主观评价和客观测试,讨论了语音清晰度、车内平均混响时间、吸声系数和声压衰减斜率的概念及相互关系,从而确定了高速道路行驶工况下的语音清晰度主要取决于车内吸声材料的性能。提出了将车内相关部位进行材料吸声改进作为改善语音清晰度的主要措施之一。 相似文献
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This study investigated the relation of symptoms of vocal fatigue to acoustic variables reflecting type of voice production and the effects of vocal loading. Seventy-nine female primary school teachers volunteered as subjects. Before and after a working day, (1) a 1-minute text reading sample was recorded at habitual loudness and loudly (as in large classroom), (2) a prolonged phonation on [a:] was recorded at habitual speaking pitch and loudness, and (3) a questionnaire about voice quality, ease, or difficulty of phonation and tiredness of throat was completed. The samples were analyzed for average fundamental frequency (F0), sound pressure level (SPL), and phonation type reflecting alpha ratio (SPL [1-5 kHz]-SPL [50 Hz-1 kHz]). The vowel samples were additionally analyzed for perturbation (jitter and shimmer). After a working day, F0, SPL, and alpha ratio were higher, jitter and shimmer values were lower, and more tiredness of throat was reported. The average levels of the acoustic parameters did not correlate with the symptoms. Increase in jitter and mean F0 in loud reading correlated with tiredness of throat. The results seem to suggest that, at least among experienced vocal professionals, voice production type had little relevance from the point of view of vocal fatigue reported. Differences in the acoustic parameters after a vocally loading working day mainly seem to reflect increased muscle activity as a consequence of vocal loading. 相似文献
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Motor fans used for cooling electric motors have long been recognized as one of the major noise sources. Current paper focuses on design of motor fan for electric motors that are used in submarines for pumping sea water. Noise reduction at source is very important and the critical task, for under water applications. An attempt has been made for reduction of motor fan noise by modification of noise sources. For this purpose computational fluid dynamics and computational aeroacoustics code FLUENT package is used to identify the noise sources and to know the overall sound pressure level of motor fan. From these results it is observed that aerodynamic noise is the dominate fan noise source. Aerodynamic noise of motor fan can be reduced by modifying fan geometry. The aerodynamic noise level of motor fan has been reduced by replacing the straight blades with various digits of NACA (National Advisory Committee for Aeronautics) 65 series airfoil sections. From the numerical results it is observed that the minimum sound pressure level for NACA 65-010 is 65.4 dB(A). These numerical results are compared with measurements in a semi-anechoic chamber. It is found that there is good agreement between numerical and experimental results. 相似文献
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