### 22.3 Synthesizers in development ¶

In addition to the above synthesizers Festival also supports CSTR’s older PSOLA synthesizer written by Paul Taylor. But as the newer diphone synthesizer produces similar quality output and is a newer (and hence a cleaner) implementation further development of the older module is unlikely.

An experimental unit seleciton synthesis module is included in `modules/clunits/` it is an implementation of black97c. It is included for people wishing to continue reserach in the area rather than as a fully usable waveform synthesis engine. Although it sometimes gives excellent results it also sometimes gives amazingly bad ones too. We included this as an example of one possible framework for selection-based synthesis.

As one of our funded projects is to specifically develop new selection based synthesis algorithms we expect to include more models within later versions of the system.

Also, now that Festival has been released other groups are working on new synthesis techniques in the system. Many of these will become available and where possible we will give pointers from the Festival home page to them. Particularly there is an alternative residual excited LPC module implemented at the Center for Spoken Language Understanding (CSLU) at the Oregon Graduate Institute (OGI).