Perceptual cost function for cross-fading based concatenation

In earlier research, we applied a linear weighted cross-fading function to ensure smooth concatenation. However, this can cause unnaturally shaped spectral trajectories. We propose context-sensitive cross-fading. To train this system, a perceptually validated cost function is needed, which is the focus of this paper. A corpus was designed to generate a variety of formant trajectory shapes. A perceptual experiment was performed and a multiple linear regression model was applied to predict perceptual quality ratings from various distances between cross-faded and natural trajectories. Results show that perceptual quality could be predicted well from the proposed distance measures.