The objective of this study is to generate stressed synthetic speech from neutral speech using a source, generator framework previously employed for stressed speech recognition. This is achieved by formulating speech parameter models for the various stressed speaking conditions and perturbing the parameters of neutral speech. The stress modeling scheme is applied to an existing low-bit rate CELP speech coder in order to investigate (i) the coder's ability and limitations in reproducing stressed synthetic speech, and (ii) our ability to perturb coded neutral speech parameters at the synthesis stage of CELP so that the resulting speech is perceived as being under stress. Four different stress perturbation algorithms are proposed and evaluated. Results from formal listener evaluations of the stress perturbed neutral speech show successful classification rates of 87% for angry speech, 75%. for Lombard effect speech, and 92% for loud speech.
Bibliographic reference. Bou-Ghazah, Sahar E. / Hansen, John H. L. (1995): "Source generator based stressed speech perturbation", In EUROSPEECH-1995, 455-458.