amsynth is a free and open-source analog modeling software synthesizer. It implements classic subtractive synthesis with dual oscillators, a resonant low-pass filter, ADSR envelopes, LFO, distortion, and reverb. The system is designed for real-time audio and MIDI processing, supporting polyphony, portamento, pitch bend, and microtonal tuning via Scala files. It can run as a standalone application using JACK, ALSA, or OSS audio drivers, or as a plugin in LV2, VST2, DSSI, and AudioUnit formats. The architecture separates the core synthesis engine (Synthesizer, VoiceAllocationUnit, VoiceBoard) from the GUI (JUCE-based with a skinnable control panel) and plugin wrappers, all sharing a common parameter system with observer pattern and value smoothing. The repository includes a large collection of preset banks, a configuration system, and internationalization support. External dependencies include JUCE for the GUI, freeverb for reverb, MTS-ESP for microtonal support, and NSM for session management.
SoundFlow is a comprehensive .NET audio framework providing cross-platform audio processing, synthesis, MIDI handling, and security features. It features a modular architecture with components, modifiers, and analyzers that can be chained together to build audio applications. The framework supports audio playback/recording, real-time effects, MIDI sequencing, audio analysis, encryption, watermarking, and fingerprinting. It includes extensive platform-specific native libraries (MiniAudio, FFmpeg, PortMidi, WebRTC APM) built for Windows, Linux, macOS, iOS, Android, and FreeBSD. The repository includes numerous sample applications demonstrating various capabilities, from simple playback to complex security-enabled audio processing.