If you want music using FluidR3_GM and FluidR3_GS you need to download the soundfonts from: 
https://osdn.net/projects/sfnet_androidframe/downloads/soundfonts/FluidR3_GM.sf2/
https://osdn.net/projects/sfnet_androidframe/downloads/soundfonts/FluidR3_GS.sf2/
and place them in /storage/roms/bios/timidity/sf2


If you want music using freepats you need to download http://freepats.zenvoid.org/freepats-20060219.zip
and unzip the file to /storage/roms/bios/timidity/freepats