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Hello Bencina,
Thank you for your reply! And also quite interesting from someone from the MTG! > Xavier was my boss and Jordi and Alex ran the group up the hall. By that I presume you are referring to Xavier Serra, Jordi Bonada, and Alex Loscos? > My recollection was that they argued that in a number of > impulse-train-generated musical timbres, it was important not only to > reproduce the harmonic content but also to reproduce an impulse > preserving phase aligment Yes this is correct. Bonada discusses this in the context of voice processing in the NBVPM and WBVPM/WBHSM techniques, which were proposed in the papers "High-Quality Voice Transforms Based on Modeling Radiated Voice Pulses in the Spectral Domain" (2004) and "Wide-Band Harmonic Sinusoidal Modeling" (2008) respectively. I believe they also did something similar for the violin, as you said, but I have not read that paper: https://urldefense.com/v3/__https://www.researchgate.net/profile/Jordi-Bonada/publication/224130820_Statistical_Modeling_of_Bowing_Control_Applied_to_Violin_Sound_Synthesis/links/0deec52aaf18e9c604000000/Statistical-Modeling-of-Bowing-Control-Applied-to-Violin-Sound-Synthesis.pdf__;!!BDUfV1Et5lrpZQ!VTe7Bj4__cgsvDLY9oi_hD2TmiMg9JSSZnza9JKc0ePZiDhl3LIt63oSQa59MZydWTGV-vlcfPvRjnmXfzdsRnpmaopZtVgh$ > impulse-train-generated musical timbres As a side note, I actually discovered the proof myself that the harmonics of a single period taken from a sequence which is itself the sum of a single pulse repeated at a fixed rate, is equivalent to sampling those same harmonics from that original proof. I have attached that derivation. > Do they give practical methods for recovering glottal closure instants > from time domain (or frequency domain) audio signals? Yes, they actually do it in the frequency domain with an algorithm they called Maximally Flat Phase Alignment. This is discussed in much detail around page 50 of Bonada's PhD thesis "Voice Processing and Synthesis by Performance Sampling and Spectral Models" (2008), although the basic MFPA algorithm was proposed in "High-Quality Voice Transforms Based on Modeling Radiated Voice Pulses in the Spectral Domain" (2004). > What parameters are you optimising? What is the cost function? Actually this is one of the hardest parts, and I will actually dedicate a whole section to it in my "thesis" (it's not really a thesis because I am not submitting to anyone or publishing it formally, but it is the conclusion to my research). For the parameters, they are all sorts of things. As random examples, the maximum frequency and amplitude deviations allowed when continuing a harmonic trajectory, or the border interpolation size in WBVPM. As I said, the cost function is complicated and basically has to be done on a case-by-case basis. Cheers. On 2026-07-27 04:03, Ross Bencina wrote: > Hello! > > Singing synthesis is not my field but I did work at MTG for a little > while during this period. Xavier was my boss and Jordi and Alex ran > the > group up the hall. My recollection was that they argued that in a > number > of impulse-train-generated musical timbres, it was important not only > to > reproduce the harmonic content but also to reproduce an impulse > preserving phase aligment (the example I recall was violin, where the > stick-slip transitions formed the impulse instants). Pretty sure there > > are impulse-aligned time domain time stretching methods known to work > well on voice too. > > I have not read [2]. Do they give practical methods for recovering > glottal closure instants from time domain (or frequency domain) audio > signals? > > What parameters are you optimising? What is the cost function? > > Best, > > Ross. > > On 26/07/2026 7:42 am, QueueSevenM wrote: >> Hello, I am posting my introduction here as recommended on the > joining >> instructions page. Unlike presumably most of the people here, I am > not >> an academic or professional researcher. I have been learning DSP in > my >> spare time over the course of >> ZjQcmQRYFpfptBannerStart >> This Message Is From an External Sender >> This message came from outside your organization. >> ZjQcmQRYFpfptBannerEnd >> >> Hello, >> >> I am posting my introduction here as recommended on the joining >> instructions page. Unlike presumably most of the people here, I am > not >> an academic or professional researcher. I have been learning DSP in > my >> spare time over the course of the last several months. What I am > mainly >> joining to post about is research I have been conducting on > improvements >> to various audio processing techniques and models, specifically with >> respect to voice processing and even more specifically, singing > voice >> synthesis. >> >> I am currently undertaking the following: >> - A system which is able to automatically find optimal values to > the >> various parameters and constants within configurations that are used > by >> various audio processing algorithms; avoiding the tedium of manually >> determining them and hopefully getting better results too. >> - A method for modeling the correlation between the phases in the >> Spectral Modeling Synthesis [1] residual and glottal closure > instants. >> [2] (which in turn cites [3]) notes the importance of this. [4] > notes >> that SMS performs particularly poorly in voiced fricatives because > of >> the loss of this correlation. >> - Improvements to the Excitation plus Resonance [5] model. >> >> In the future, I will also work on improvements to Wide-Band > Harmonic >> Sinusoidal Modeling [6]. >> >> References: >> [1] Serra, Xavier. "A System for Sound >> Analysis/Transformation/Synthesis based on a Deterministic plus >> Stochastic Decomposition". Stanford University, PhD Dissertation, > 1989. >> [2] Bonada Sanjaume, Jordi; Serra, Xavier. "Synthesis of the > Singing >> Voice by Performance Sampling and Spectral Models," in IEEE Signal >> Processing Magazine, vol. 24, no. 2, pp. 67-79, March 2007. >> [3] Kob, Malte. "Physical Modeling of the Singing Voice". > Institute of >> Technical Acoustics, >> Aachen University, PhD dissertation, 2002. >> [4] Bonada Sanjaume, Jordi; Loscos, Alex; Mayor, Oscar; Kenmochi, >> Hideki. "Sample-Based Singing Voice Synthesizer using Spectral > Models >> and Source-Filter Decomposition". Proceedings of Interspeech 2003. >> [5] Bonada Sanjaume, Jordi; Celma, Oscar; Loscos, Alex; Ortola, > Jaume; >> Serra, Xavier. "Singing Voice Synthesis Combining Excitation plus >> Resonance and Sinusoidal plus Residual Models". Pompeu Fabra > University, >> 2001. >>
