Wideband acoustic modeling of speech

语音和歌唱的声学特性主要在高达5 kHz的低频下进行研究，而更高的频率被认为基本上无关紧要。然而，最近有证据表明，语音的高频成分比以前认为的起着更重要的作用，并且携带着例如非语言信息。目前的知识的高频成分的语音，其方向性依赖的辐射，以及它们的关系，清晰度是相当有限的，部分原因是他们的调查的困难。一个潜在的合适的方法来研究这些问题的基础上的宽带三维声道声学模拟。然而，当前的3D模拟方法或者在计算上非常昂贵（例如，有限元方法），或者需要声道的高度简化的几何形状（多模态方法）。在这里，我们提出了一种混合方法的发展，覆盖整个可听频率范围的声道的三维声学模拟，是快速和物理准确的同时。其基本思想是将联合收割机的解析多模态方法与二维有限元数值方法相结合来计算模态基函数。该混合声学模型在发音语音合成器VocalTractLab的框架中实现和优化，其中它与声道的现有3D发音模型相结合，以实现连接语音发音的物理准确宽带合成。所提出的方法通过对声道的3D打印复制品进行宽带声学测量来客观评估，并通过对人类听众的感知测试来主观评估。

The acoustic properties of speech and singing have been mainly studied at low frequencies of up to 5 kHz, while higher frequencies have been considered essentially irrelevant. More recently, however, evidence has emerged that the high-frequency components of speech play a more significant role than previously believed, and carry, for example, paralinguistic information. The current knowledge about the high-frequency components of speech, their directivity-dependent radiation, and their relation to articulation are rather limited, partly due to the difficulties of their investigation. A potentially suitable approach to study these issues is based on the wideband 3D acoustic simulation of the vocal tract. However, current 3D simulation methods are either computationally very expensive (e.g., finite element methods), or require strongly simplified geometries of the vocal tract (multimodal method). Here, we propose the development of a hybrid method for the 3D acoustic simulation of the vocal tract that covers the whole audible frequency range and is fast and physically accurate at the same time. The basic idea is to combine the analytical multimodal approach with a numerical 2D finite element approach to compute the modal basis functions. This hybrid acoustic model is implemented and optimized in the framework of the articulatory speech synthesizer VocalTractLab, where it is combined with an existing 3D articulatory model of the vocal tract for the physically accurate wideband synthesis of connected speech utterances. The proposed method is evaluated objectively by means of wideband acoustic measurements of 3D-printed replicas of the vocal tract, and subjectively by a perception test with human listeners.