The 'inboard' mounted reeds on the Jeffries 38 system (and presumably the larger Anglos and duets too) have a slightly different tone to those mounted at the side of the reed pan. This problem is most acute on the left side thumb button reeds, where the tone is distinctly nasal in comparison to their 'outboard'cousins. Because of the position of this button's reed chamber, the air hole is drilled through both the pad board and the action plate and is thus twice the depth of all the other holes.