The Synthesis Toolkit (STK) is an open source API for real time audio synthesis with an emphasis on classes to facilitate the development of physical modelling synthesizers. It is written in C++ and is written and maintained by Perry Cook at Princeton University and Gary Scavone at CCRMA. It contains both low-level synthesis and signal processing classes (oscillators, filters, etc.) and higher-level instrument classes which contain examples of most of the currently available physical modelling algorithms in use today. The STK is used widely in creating software synthesis applications, many of the hardware implementations of which would be protected by patents by Yamaha and other synthesizer manufacturers. Versions of the STK instrument classes have been integrated into ChucK, Csound, Real-Time Cmix, Max/MSP (as part of PeRColate) and SuperCollider ( http://sourceforge.net/projects/sc3-plugins/ ).
