SFF2 is sometimes known as "SFF GE" meaning "Style File Format (Guitar Edition)". Quoting the old S950 owner's manual:
“SFF (Style File Format)” is an original Style file format by Yamaha which uses a unique conversion system to provide high quality
automatic accompaniment based on a wide range of chord types. “SFF GE (Guitar Edition)” is an enhanced format of
SFF, which features improved note transposition for guitar tracks.
The three ranges (high, mid, low) mentioned by Jørgen provide better support for MegaVoices which split MIDI notes into regular sounding notes (below C6) and special effect notes (C6 and above). The high settings can be set for SFX notes while the mid and low settings handle the "regular" notes. This arrangement lets Yamaha handle a MegaVoice part in a single style Part.
That's probably TMI.
-- pj
Jørgen, did SFF GE (SFF2) add NTR=GUITAR and NTT={ALL-PURPOSE, STROKE, ARPEGGIO}? Thanks.