8O
t'étonnes pas de te faire tailler, j'ai trouvé la réponse en 2 secondes...
The ME-20 features on on-board expression pedal to control volume, as well as a wah effect. The built-in switch underneath the expression pedal makes it quick and easy to toggle between controlling volume or wah. Here’s how:
Press the pedal all the way forward, and then give it a stronger push. When the WAH 1 indicator lights up red, the pedal is controlling wah. When the indicator is unlit, the pedal is controlling volume.
Each time you press the pedal forward and give it a solid push, it toggles between 2 wah and volume.
en gros, ça marche comme une pédale wah!!!