They are not "midi" musics, they come from the Amiga world, they are called modules and they correspond to files having extensions .mod ou .s3m, or some others...
I had difficulties to find a freeware which plays these modules. If I am not enough fan to judge the quality of the sound (which is also depending of hardware, parameters...), I like the ability to play the modules in continuity, as in a jukebox.
To listen an electronic music, coming from elsewhere
Created by Olivier Lapicque, this program may be downloaded on the author site (around 180 Kb, zip format).