Hi mario,
the internal sound of X1 are totally reprogrammable and upgradable via Floppy. If ketron want to relase a new sound upgrade (like SD1...) you can upload in X1 via floppy.
If you try to analyze the firm000.snd file with an editor, you can find a lot of sound information, or try to open this with a wav editor like cooledit, you find a sample off snaredrum!
Ketron can upgrade all the internal soundflashmemory of X1 !!!