SNDH is a music
format used for a great deal of the music on the Atari ST
. It contains both the player and the music data, making it very flexible for the musician
Due to the fact that the player code is included in the file, there are few, if any, non-Atari players around that can actually accomplish the full range of effects used by the composers.
When it comes to player software on the atari, there is "SND Player", which can be found at http://sndplayer.atari.org/.