Titze Ingo R, Worley Albert S
National Center for Voice and Speech, The Denver Center for the Performing Arts, Denver, CO 80204, USA.
J Acoust Soc Am. 2009 Sep;126(3):1530. doi: 10.1121/1.3160296.
Nonlinear source-filter theory is applied to explain some acoustic differences between two contrasting male singing productions at high pitches: operatic style versus jazz belt or theater belt. Several stylized vocal tract shapes (caricatures) are discussed that form the bases of these styles. It is hypothesized that operatic singing uses vowels that are modified toward an inverted megaphone mouth shape for transitioning into the high-pitch range. This allows all the harmonics except the fundamental to be "lifted" over the first formant. Belting, on the other hand, uses vowels that are consistently modified toward the megaphone (trumpet-like) mouth shape. Both the fundamental and the second harmonic are then kept below the first formant. The vocal tract shapes provide collective reinforcement to multiple harmonics in the form of inertive supraglottal reactance and compliant subglottal reactance. Examples of lip openings from four well-known artists are used to infer vocal tract area functions and the corresponding reactances.
非线性源滤波器理论被用于解释两种截然不同的男性高音演唱方式（歌剧风格与爵士转音或戏剧转音）之间的一些声学差异。文中讨论了几种风格化的声道形状（夸张描绘），它们构成了这些演唱风格的基础。据推测，歌剧演唱使用的元音会朝着倒置扩音器的口型进行修改，以便过渡到高音区。这使得除基频外的所有谐波都能“提升”到第一共振峰之上。另一方面，转音演唱使用的元音则始终朝着扩音器（类似小号）的口型进行修改。这样一来，基频和二次谐波都会保持在第一共振峰之下。声道形状通过声门上惯性电抗和声门下顺应性电抗的形式，为多个谐波提供集体增强作用。文中使用了四位知名艺术家的唇部开口示例来推断声道面积函数及相应的电抗。
