Korg K25 Owner's Manual page 21

Volume message filter
You can prevent the internal sound engine from receiving volume change messages.
If the Volume message filter is set to "On", the K61P's internal sound generator will
accept volume(07) message from Knob1, Knob2 and the Slider if they are assigned
control change cc#07.
If it's set to "Off", the K61P's internal sound generator will reject volume(07) message
from Knob1, Knob2 and the Slider even if they are assigned control change cc#07.
1
Hold down [BANK] button until the K-Series enters the Setting mode.
2
Press the Program 8 [HARPSI 2/CHOIR/STRINGS 2] button (the button will flash).
C1 C2
3
Press note C4(On) or C#4(Off) to select the setting.
CC#07 flow chart
ON
Computer
Controller
K61P
4
Press [BANK] key to quit setting mode.
C3 C4 C5
OFF
SG
* SG: Sound Generator
SG's volume knob controls
SG's volume level.
Owner's Manual
C6 C7 C8
Computer
SG
Controller
K61P
21