AlsaModularSynth is a realtime modular synthesizer and effect processor. It features MIDI controlled modular software synthesis, realtime effect processing with input capture, full control of all synthesis and effect parameters via MIDI, an integrated LADSPA browser with search capability, and JACK support.
Chips is a Python library for designing hardware devices that provides a high-level device modelling language. Native simulations integrate with Python so you can use Python extension modules such as Scipy, Numpy, Matplotlib, and PIL to provide a rich verification environment. Device models can be automatically translated into synthesizable VHDL, and highly optimized soft-processors are generated for an efficient implementation. A plugin mechanism is provided so that additional code generators can be added. C++ and Graphviz plugins are provided. Existing VHDL IP can be imported, and seamless co-simulation of C++ and VHDL outputs is is supported.
hexter is a software synthesizer that models the sound generation of a Yamaha DX7 synthesizer. It can easily load most DX7 patch bank files, edit those patches via a built-in editor or MIDI sys-ex messages, and recreate the sound of the DX7 with greater accuracy than any previous open source emulation (that the author is aware of). It operates as a plugin for the DSSI Soft Synth Interface.