In 2017, a monograph Elements of Human Voice was published by World Scientific Publishing. In that book, based on an analysis of large number of experimental data, especially simultaneously acquired voice signals, electroglottagraph signals, and temporal variations of pressures immediately below and above the vocal folds during phonation, a new theory of human voice production, the timbron theory, is systematically presented. It might replace the sixty-years-old source-filter theory to become the standard theory of human voice production. According to ResearchGate, as of November 2022, that book has 5,276 readings.
According to a recent article on Journal of Voice coauthored by J Svec, HK Schutte, CJ Chen and IR Titze, the timbron theory has been acknowledged as the correct theory of human voice production by many researchers in the voice-science community.
Another article published in 2020 on Journal of Voice, Pitch-Synchronous Analysis of Human Voice, presented a pitch-synchronous spectrogram as a much-improved replacement of the traditional spectrogram with fixed windows. It is a graphical tool for the analysis of voice signals according to the timbron theory of human voice production.
The artificial intelligence group of the Free University of Brussel published two papers showing the superiority of the pitch-synchronous method for the analysis of human voice, especially the extraction of formants. Those two papers also represent a confirmation of the timbron theory of human voice production by that group.
The timbron theory of human voice production is the scientific basis for a new generation of speech technologies, especially embodied in the following US patents:
US Patent 8719030, "System and Method for Speech Synthesis".
US Patent 8744854, "System and Method for Voice Transformation".
US Patent 8886539, "Prosody Generation Using Syllable-Centered Polynomial Representation of Pitch Contours".
US Patent 8942977, "System and Method for Speech Recognition Using Pitch-Synchronous Spectral Parameters".
US Patent 9135923, "Pitch-Synchronous Speech Coding Based on Timbre Vectors".
Columbia Technology Ventures (CTV) is currently handling the licensing of those patents.