Hymn Midi Player for Schlicker Organs.
For building instructions see building
For general MIDI editing, I recommend Aria Maestosa. It is easy to use, and works on nearly any platform. This guide will assume that you are using that tool.
NOTE: MIDI files created of a copyright work may themselves be considered copyright and not fall under fair-use. Always check with the license for fair-use grants and necessary attributions.
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Copyright (c) 1999-2018, Craig Stuart Sapp
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RtMidi: realtime MIDI i/o C++ classes
Copyright (c) 2003-2019 Gary P. Scavone