A New Distance Measure for Costing Spectral Discontinuities in Concatenative Speech Synthesisers

Abstract

In many modern concatenative speech synthesisers the unit sequence used to synthesise each sentence is determined at runtime by a search algorithm seeking to optimise a multidimensional cost function. One of these costs is usually some form of spectral continuity cost, computed between the end of one segment and the start of the following segment, intended to ensure that the synthetic speech does not contain any unpleasant spectral discontinuities. This paper presents the results of listening tests conducted to evaluate the performance of several possible continuity measures. It also describes a new continuity measure developed at IBM which substantially out-performs all other measures tested.