We introduce real-time and interactive tools for assisting vocal training. In this presentation, we demonstrate mainly a tool based on real-time visualizer of fundamental frequency candidates to provide information-rich feedback to learners. The visualizer uses an efficient algorithm using analytic signals for deriving phase-based attributes. We start using these tools in vocal training for assisting learners to acquire the awareness of appropriate vocalization. The first author made the MATLAB implementation of the tools open-source. The code and associated video materials are accessible in the first author's GitHub repository.

This article focuses on the research tool for investigating the fundamental frequencies of voiced sounds. We introduce an objective and informative measurement method of pitch extractors' response to frequency-modulated tones. The method uses a new test signal for acoustic system analysis. The test signal enables simultaneous measurement of the extractors' responses. They are the modulation frequency response and the total distortion, including intermodulation distortions. We applied this method to various pitch extractors and placed them on several performance maps. We used the proposed method to fine-tune one of the extractors to make it the best fit tool for scientific research of voice fundamental frequencies.