Spent today producing this version of a movement form Carnival of the Animals by Saint Saëns.
It started out as a midi file from the IMSLP site produced by TheMusicMan03 with a Creative Commons 4.0 licence. I edited this in MuseScore2 so that each track would be able to play in Sonic Pi. (To do this I had to create two further tracks to split up a piano track that was too complex to play directly on Sonic Pi) I ended up with 13 instrument tracks, which were then exported as MusicXML files and converted to Sonic Pi notation using a processing script, I then added a midi function to play each of these tracks (allowing for the fact that some contained chords). I played the file to the free vmpk virtual midi piano with fluid_synth GM library installed, and selected the instruments to play using the midi_pc command in Sonic Pi 3.1 This was also utilised to switch the strings output between pizzicato and arco voices a different stages of the piece. The resulting audio output was then fed back into Sonic Pi as a live_audio input (I used Amoeba Software’s LoopBack utility to do this) where I applied some amplification and reverb, and the audio was recorded inside Sonic Pi as it played. This .wav file was then converted to .flac format using Audacity and uploaded to soundcloud where you can listen to it.