The Expression (EXP) pedal on the ME-80 can control not only Volume level, but also various effects. Here's how to activate and select a desired Pedal effect for a Patch. 

1. Place the ME-80 on a hard floor surface. 

2. Move the EXP pedal all the way toe-forward until it stops, and then give it a strong press. The PEDAL FX LED will light. (Note: It may take a good amount of pressure to activate the Pedal FX.)

3.  Turn the PEDAL FX knob to choose the desired effect. 

WAH - Creates a WAH effect. 

VOICE - An effect that simulates the sound of a human voice 

+1 OCT - Varies the pitch from the original sound to one octave up. 

+2 OCT - Varies the pitch from the original sound to two octaves up. 

-1 OCT - Varies the pitch of the original  sound to one octave lower. 

FREEZE - Sustains the tone of the guitar. 

OSC DELAY - Creates an oscillating Delay effect. 

OD/DS - Controls the drive of the selected OD/DS effect. 

MOD RATE - Controls the modulation rate of a selected effect within the MOD section. 

DELAY LEVEL - Controls the Delay effect level.

4. Once you have chosen an effect, you can write (store) the settings into a User patch location by pressing the WRITE button.