A Comparative Study of the Performance of HMM, DNN, and RNN based Speech Synthesis Systems Trained on Very Large Speaker-Dependent Corpora

This study investigates the impact of the amount of training data on the performance of parametric speech synthesis systems. A Japanese corpus with 100 hours’ audio recordings of a male voice and another corpus with 50 hours’ recordings of a female voice were utilized to train systems based on hidden Markov model (HMM), feed-forward neural network and recurrent neural network (RNN). The results show that the improvement on the accuracy of the predicted spectral features gradually diminishes as the amount of training data increases. However, different from the “diminishing returns” in the spectral stream, the accuracy of the predicted F0 trajectory by the HMM and RNN systems tends to consistently benefit from the increasing amount of training data.