Mind you, timidity was wonderful (well it was best under windows XP where it did system wide midi with no configuration). But I could use it to play midi files from the command line, or with VMPK, a toy piano (sending a huge peak of garbage on my right speaker when it starts), and that's all.
With Fluidsynth I had no peak in VPMK and I ended up getting music under dosbox! and I ended up getting a smooth MS-DOS doom2!, by setting a stupid high cycle number in dosbox.conf and tweaking the video output parameters. It didn't sound as good as I remember with using timidity on Windows but that's because my flat is too small and maybe Linux damaged my speakers.
I still have no music in prboom (with timidity I could get some with the incomplete and garbage "freepats.cfg sounds" ; a known and unresolved bug prevented from using a soundfont). Nothing in prboom.cfg, nothing in in-game menus, nothing in prboom manpage. I have to look for garbage pages in google, such as end of this one http://prboom.sourceforge.net/linux.html
and this one http://www.libsdl.org/projects/SDL_mixer/
So, under linux prboom uses garbage midi synth in "SDL_mixer" that uses timidity but only supports Gravis Ultrasound Patch (a thing that was hot in 1994 and ignored outside the MS-DOS demo scene). Under Windows prboom supports system wide, real midi. This is nuts.