GTG 44 S special features.
Filter - The red/green filter switch alternates between two filter types. In the red position cut off and resonance gets steeper and the overall sound becomes warmer/fatter. The switch is useful for either adding fullness to the sound (red) or removing unpleasant artifacts (green), like rumble or distortion, depending on the other filter settings. It also changes the character of the sound when using BP, HP and BR filter settings (note that in some cases you will not hear much difference when switching back and forth this switch, since it depends on the other filter settings.
LFO - The LFO's are different in the way that speed control on LFO 2 when set to maximum key follow and rate can make a sound similar to ring modulation (for bell-like sounds). LFO 1 has a delay function and also modulates filter resonance. The synth has a pitch envelope for Osc 2 so you can make snappy attacks or sync modulated sweeps. There's a sub-oscillator for deep bass sounds.
Vibrato - Vibrato (wheel) adds vibrato to oscillator 2 only. When Sync is on the vibrato therefore will be heard as "frequency modulation" of the sync'ed output instead of the usual pitch vibrato sound (Nice for sweeping pad sounds etc.)