Yamaha MU90R Owner's Manual page 60

Level
HPF Cutoff Frequency (HPF Cutoff)
This determines the cutoff frequency of the high pass filter (HPF). The
HPF filters out frequencies lower than the cutoff point and "passes" the
higher frequencies. Lower cutoff values preserve the fundamental and
lower overtones of the sound, while higher values create a thinner,
brighter tone.
Selected Part and MIDI channel
These frequencies are
"cut" or filtered out.
LPF Cutoff Frequency setting
Graphically shows HPF Cutoff Frequency setting for each Part.
Level
MULTI MODE
Resonance
Frequency
These frequencies are
"passed" or let through.
HPF Cutoff Frequency setting
Frequency
5 1