Reed tension is the force that opposes the reeds opening, essentially the springiness of the reed material. It is normally set by the thickness of the reed material and the number of petals (thicker and less petals = more tension) I am not sure how they would adjust this other than with increasing the size of the washers, or reed stop, on the retaining screws to shorten the effective length of the "spring". Someone help me out here. Cam.