Roland FXM

[dalecarlica]

Hi there
Does ANYBODY out there know exactly HOW the FXM function is generated on the Roland XP/JV series?? It's not mentioned in the manual at all! I read somewhere that the wave itself is multiplied(modulated) by a SQUARE(?) and that the amount(pitch/filter/level) relates to the depth of the effect.
However, when taking a sax wave and applying FXM, I notice that only CERTAIN notes produce a really cool gutteral GROWL. It seems that the FXM uses the square-modulator which is set to pitch-KF 0. Every octave the growl virtally disappears.........only to become more pronounced again.
I tried emulating this by using STRUCTURE 5/7/9$10 and assigning a square/pulse wave as partial1 and sax as partial2 and setting partial1's KF to 100, to try to replicate that perfect growl over the whole range of notes. Alas!
Has ANYONE experimented on this as well, or am I the only keyboardist in the world that's obsessed with Sax Growls???