Vocal training is difficult because the muscles that control pitch, resonance, and phonation are internal and invisible to learners. This paper investigates how Electromyography (EMG) and ultrasonic imaging (UI) can make these muscles observable for training purposes. We report three studies. First, we analyze the EMG and UI data from 16 singers (beginners, experienced & professionals), revealing differences among three vocal groups of the muscle control proficiency. Second, we use the collected data to create a system that visualizes an expert's muscle activity as reference. This system is tested in a user study with 12 novices, showing that EMG highlighted muscle activation nuances, while UI provided insights into vocal cord length and dynamics. Third, to compare our approach to traditional methods (audio analysis and coach instructions), we conducted a focus group study with 15 experienced singers. Our results suggest that EMG is promising for improving vocal skill development and enhancing feedback systems. We conclude the paper with a detailed comparison of the analyzed modalities (EMG, UI and traditional methods), resulting in recommendations to improve vocal muscle training systems.

翻译：嗓音训练具有挑战性，因为控制音高、共鸣和发声的肌肉属于人体内部结构，学习者无法直接观察。本文探讨如何通过肌电图（EMG）和超声成像（UI）使这些肌肉在训练过程中变得可视化。我们报告了三项研究。首先，我们分析了16名歌手（包括初学者、有经验者及专业人士）的EMG与UI数据，揭示了三个歌唱群体在肌肉控制熟练度上的差异。其次，我们利用收集的数据构建了一个系统，将专家的肌肉活动以可视化形式作为参考。该系统在12名初学者的用户研究中得到验证，结果显示EMG能够突出肌肉激活的细微变化，而UI则提供了声带长度与动态特性方面的洞察。再次，为将我们的方法与传统方法（音频分析和教练指导）进行对比，我们组织了由15位经验丰富的歌手参与的焦点小组研究。结果表明，EMG在提升歌唱技能发展和增强反馈系统方面具有潜力。最后，我们对所分析的模态（EMG、UI及传统方法）进行了详细比较，据此提出改进声带肌肉训练系统的建议。