This is a VST effect that emulates EAX (Environmental Audio Extensions) reverb. EAX was a standard used in late 90s to early 2000s Creative Labs sound cards to add audio effects to games. This VST is based on the openal-soft EAX Reverb Implementation which was ported to c++, and subsequently backported to C.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
Have fun!