Yamaha MU90R Owner's Manual page 116

The Insertion effects are set up for Insertion routing and can be
applied only to a single selected Part. Refer to About the Effect
Connections — System and Insertion on page 106 for more
information.
Type
NOTE
When Thru is selected, no effect is applied, and none of the parameters are available (with
the exception of the Part parameter).
Dry/Wet Balance
This determines the balance between the direct, unprocessed signal
(dry) and the processed sound (wet). Use this parameter together
with the Output Level parameter above to obtain the desired overall
sound.
Assignable Controller 1 Insertion 1/2 Control (AC1INS1/2Ctrl)
This determines the degree to which Assignable Controller 1 (AC1)
affects the MIDI-controllable parametes of the Insertion effects.
Each of the Insertion effect types have one parameter which can be
controlled by the AC1. (For details, see the "Effect Parameter List"
of the "SOUND LIST & MIDI DATA" booklet.) This parameter is
not available in the performance mode.
EFFECT EDIT MODE
107