If you want to get a sense of the sonic possibilities of the Korg Opsix, you could do a lot worse than checking out these audio demos by Jexus.
In the first video, above, Jexus demos 60 custom Opsix sounds in 12 minutes. In the second video, below, the sonic onslaught continues:
Jexus notes that, while the build of the Opsix doesn’t match that of classic Yamaha FM synths, “To say that it’s a great synth for modern leads, acoustic plucks, industrial / techno sequences and ambient pads / soundscapes is a criminal understatement.”
You can buy Jexus’s complete collection of 270 patches for the Opsix for 26 Euros