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A Pulse Model in Log-domain for a Uniform Synthesizer

Published version
Peer-reviewed

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Authors

Degottex, G 
Lanchantin, P 

Abstract

The quality of the vocoder plays a crucial role in the performance of parametric speech synthesis systems. In order to improve the vocoder quality, it is necessary to reconstruct as much of the perceived components of the speech signal as possible. In this paper, we first show that the noise component is currently not accurately modelled in the widely used STRAIGHT vocoder, thus, limiting the voice range that can be covered and also limiting the overall quality. In order to motivate a new, alternative, approach to this issue, we present a new synthesizer, which uses a uniform representation for voiced and unvoiced segments. This synthesizer has also the advantage of using a simple signal model compared to other approaches, thus offering a convenient and controlled alternative for future developments. Experiments analysing the synthesis quality of the noise component shows improved speech reconstruction using the suggested synthesizer compared to STRAIGHT. Additionally an experiment about analysis/resynthesis shows that the suggested synthesizer solves some of the issues of another uniform vocoder, Harmonic Model plus Phase Distortion (HMPD). In text-to-speech synthesis, it outperforms HMPD and exhibits a similar, or only slightly worse, quality to STRAIGHT’s quality, which is encouraging for a new vocoding approach.

Description

Keywords

parametric speech synthesis, vocoder, pulse model

Journal Title

Proceedings of the 9th ISCA Speech Synthesis Workshop

Conference Name

9th ISCA Speech Synthesis Workshop

Journal ISSN

Volume Title

Publisher

International Speech Communication Association
Sponsorship
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 655764. The research for this paper was also partly supported by EPSRC grant EP/I031022/1 (Natural Speech Technology).