Titze Ingo R
Department of Speech Pathology and Audiology, The University of Iowa, Iowa City, Iowa 52242, USA.
J Acoust Soc Am. 2008 May;123(5):2733-49. doi: 10.1121/1.2832337.
A theory of interaction between the source of sound in phonation and the vocal tract filter is developed. The degree of interaction is controlled by the cross-sectional area of the laryngeal vestibule (epilarynx tube), which raises the inertive reactance of the supraglottal vocal tract. Both subglottal and supraglottal reactances can enhance the driving pressures of the vocal folds and the glottal flow, thereby increasing the energy level at the source. The theory predicts that instabilities in vibration modes may occur when harmonics pass through formants during pitch or vowel changes. Unlike in most musical instruments (e.g., woodwinds and brasses), a stable harmonic source spectrum is not obtained by tuning harmonics to vocal tract resonances, but rather by placing harmonics into favorable reactance regions. This allows for positive reinforcement of the harmonics by supraglottal inertive reactance (and to a lesser degree by subglottal compliant reactance) without the risk of instability. The traditional linear source-filter theory is encumbered with possible inconsistencies in the glottal flow spectrum, which is shown to be influenced by interaction. In addition, the linear theory does not predict bifurcations in the dynamical behavior of vocal fold vibration due to acoustic loading by the vocal tract.
本文提出了一种发声过程中声源与声道滤波器之间相互作用的理论。相互作用的程度由喉前庭（喉上管）的横截面积控制，该横截面积会提高声门上声道的惯性电抗。声门下和声门上的电抗都可以增强声带的驱动压力和声门气流，从而提高声源处的能量水平。该理论预测，在音高或元音变化过程中，当谐波通过共振峰时，可能会出现振动模式的不稳定性。与大多数乐器（如木管乐器和铜管乐器）不同，通过将谐波调谐到声道共振来获得稳定的谐波源频谱，而是将谐波置于有利的电抗区域。这允许声门上惯性电抗（以及较小程度上的声门下顺应性电抗）对谐波进行正增强，而不会有不稳定的风险。传统的线性源滤波器理论在声门气流频谱中存在可能的不一致性，研究表明声门气流频谱会受到相互作用的影响。此外，线性理论无法预测由于声道的声学负载导致的声带振动动力学行为中的分岔现象。
