The Syter is a real-time computer music system developed at Groupe de Recherches Musicales (GRM) in Paris since the mid-seventies. It was used until the mid-nineties before being replaced by GRM Tools.
Before the Syter – Before Syter, the GRM computer music activity took place mainly in the field of deferred-time through the use of Music V by Max Mathews and through the development of Studio 123 software. The Syter represents a return to real time. Return, because this possibility had already been explored with Syntom: a failed project developed in collaboration with Knut Wiggen and the EMS in Stockholm.
The early years – The turning point for the Syter occurs with the arrival of Jean-François Allouis at GRM. During her years of work for the Studio 123 package, showed a greater interest in real-time computer music applications, and for this reason he pushed the research towards the project Syter (originally an acronym of SYnthèse en TEmps Réel ,then SYstème en TEmps Réel). The project was initiated in 1975. In 1977 the first prototype was finished and used for the realization of Cristal by François Bayle. The subsequent years was followed by several modified and improved versions, until the final in 1984, Syter 3, considered the first fully operational model. The previous version, however, called Syter 2, was considered a failure: the processor, in fact, was devoid of a dedicated computer to its control, making its use too limited. For this question Syter 2 was never used. The working group organized by Jean-François Allouis included Jean-Yves Bernier (responsible for the graphics), Richard Bulski (responsible for the hardware connections and software), Hugues Vinet (that developed editing software) and Yann Geslin (responsible for graphical interface). To these are added Pierre Dutilleux, Andre Prot and other staff members of Digilog, responsible for industrial development that led to the construction of ten copies between 1985 and 1987.
Hardware – The GRM system was equipped with a signal processor for real-time called Syter, connected to a PDP 11/23 mini computer (Bull version). Provided, also, a physical memory for data storage, two input devices and eight for output. Could be managed through a mouse and a graphical display. Allouis was responsible for the implementation of the processor, Input and Output converters, and MIDI interface. The previous work for the Studio 123 package, wasn’t lost: many different features and algorithms, previously used, were adapted and introduced in the new system.
GUI – One of the most interesting innovation was undoubtedly the presence of a graphical user interface, controlled through the mouse, that providing a real-time control of various parameters. This interface reproduced a classic mixing desk equipped with sliders, triggers and joysticks, virtual of course. The GUI software was called SYG.
Software features – In computer science perspective, the Syter was structured into modules that could be combined together to form instruments. Combination of these modules was via programming language. Among these modules are oscillators, envelopes, harmonizers, delay, noise generators, and so on. The approach, therefore, is modeled on the UG system introduced with the Music III. It should be noted that in the case of Syter there were also several versions of the same modules, this is because each version had been adapted to the specific needs of those composers who showed particular needs. Just as had happened with Studio 123, also for the Syter were organized workshops, for stimulate the composers to use it. More than 300 works have been realized with this system.
Syter applications – The GRM system could be used for various functions such as sound synthesis, analysis of the sound spectrum, and even image processing. Regarding the analysis should be noted that the CNRS working group, in Marseille, which included among others Daniel Arfib and Jean-Claude Risset, integrated in Syter the Wavelet synthesis, a method used for analysis and resynthesis of sound signals. Other particular Syter applications have been made in industrial and military for which Digilog has developed a special version called Genesis.
Syter’s heritage – The Syter was used until 1995. It is still present at the GRM, but clearly fell into disuse. Like many elements of the Studio 123 were reused in Syter, in the same way different modules of the latter were then reused in the GRM Tools.
For this topic I’ve read:
 Daniel Teruggi, Technology and musique concrète: the technical developments of the Groupe de Recherches Musicales and their implication in musical composition, Organised Sound, Vol. 12 , 2007.
 Yann Geslin, Digital Sound and Music Transformation Environments: A Twenty-year Experiment at the “Groupe de Recherches Musicales”, Journal of New Music Research, Vol. 31 .
 Richard Kronland-Martinet, The Wavelet Transform for Analysis, Synthesis, and Processing of Speech and Music Sounds, Computer Music Journal, Vol. 12 , 1988.