This is the synthesizer plug-in Surge which (@kurasu) Claes Johanson previously sold as a commercial product via the company vember audio.
As he is too busy with other projects and no longer wanted to put the effort into maintaining Surge across multiple platforms, he decided to give it new life as an open-source project.
It was originally released in 2005, and was one of Claes’ first bigger projects. It is reliable and sounds great.
The codebase was migrated from before an unfinished 1.6 release, which improves on the last released 1.5.3 in a number of ways:
It uses a newer version of the VSTGUI framework. This has caused a lot of graphical bugs, with some still needing to be fixed. But it will enable the creation of a port for both 64-bit macOS and Linux.
Support for VST3
Support for MPE
New analog mode for the ADSR envelopes
Surge currently builds with Windows and macOS (AudioUnit, VST2, VST3), and getting it to build on Linux again should be doable with some effort.
While Surge is an on-going effort, the newest builds and installers for Windows 64-bit and macOS 64-bit (VST2,VST3,AU) exist at https://github.com/surge-synthesizer/releases/releases
The official website is gathering steam, too, check it out at https://surge-synthesizer.github.io/
At least Pentium 4 CPU.
64-bit Windows or macOS.