My top E and B strings were choking out above the 12th fret on my resonator (Gretsch Honeydipper). At first I suspected wear on wooden biscuit-bridge but adjusting the strings on to fresh adjacent wood had no effect. So I took the cone out and sat it on a levelled flat glass surface and using a spirit level observed that the top of the cone where the biscuit sits was not in parallel to the cone's base, but dipped one side.
The guitar has not taken a hit to the bridge which is covered anyway by a metal palm shield.
I'm assuming the top of the cone should be parallel to the base so I'm wondering what could have caused this?
I would have thought the cone wouldn't be compressed out of alignment by normal string pressure?
In the short term I've put the cone back in with the high side aligned with the top E which helps a touch.
Time for a new cone?
(pronounced: equal-sequel) "I suffered for my art.. now it's your turn"