The Yamaha FS1R is a sound synthesizer manufactured by the Yamaha Corporation from 1998 to 2000. Based on Formant synthesis, it also has FM synthesis capabilities similar to the DX range. Its editing involves 2,000+ parameters in any one 'performance', prompting the creation of a number of third party freeware programming applications. The synth was discontinued after 2 years, probably in part due to its complexity (particularly the formant sequencing), poor front-panel controls, brief manual and limited polyphony.
Read more about Yamaha FS1R: Formant Sequencing, Problems and Shortcomings, Notable Users