Steinberg Pro24 was one of the first pattern-based midi sequencers from 1986 for the Atari 520ST and 1040ST. It was an improvement over the Pro16, allowing for 24 midi tracks. It saved sequences files as.sng files. These, however, are not the same as the .sng files saved in Texture, Kurzweil, Korg, or Voyetra sequencers. We can, however, convert each of these types of files.
