Yamaha SY85 Owner's Manual page 67

Type (Filter type)
66
VOICE EDIT MODE /
Determines the type of filter response used.
The "THRU" (THROUGH) setting turns the filter OFF.
The "LPF" (Low Pass Filter) and "LPF12" settings produces a filter re-
sponse that allows only frequencies below the cutoff frequency (See "Cutoff"
above) to pass. The "LPF" filter type has a steep 24-dB/octave cutoff slope,
while the "LPF12" type has a gentler 12-dB/octave slope.
The illustrations here are not available.
The "HPF" (High Pass Filter) setting produces a filter response that allows
only frequencies above the cutoff frequency (See "Cutoff" above) to pass.
The illustrations here are not available.
3:Filter