If the .ALL files contain only MIDI data, and if you really want to try some hardcore hacking, there’s a freeware Cubase Lite for Atari ST which will work fine in the Steem emulator …
If the .ALL files contain only MIDI data, and if you really want to try some hardcore hacking, there’s a freeware Cubase Lite for Atari ST which will work fine in the Steem emulator …