The Elekfor Formant synthesizer was a DIY modular synthesizer whose design was published in Elektor, a magazine for electronics hobbyists, starting in 1977. It was designed by Cyril Chapman. The complete design was published as a book in 1979.C. Chapman (in french) FORMANT synthétiseur — Description, Réalisation, Réglage, Utilisation (1st ed.), Elektor sàrl ISBN 2-86408-002-8
The Formant had a similar set of modules to a Moog modular synthesizer. A typical Formant setup included three VCOs, two VCFs, dual VCAs, one or more ADSR waveform generators, an LFO module and a noise source.
References
External links https://www.elektormagazine.de/magazine/elektor-197612/56155