I swapped a fender bridge plate for another fender bridge plate. I changed one set of Clusons for another set. The only difference is the amount of aging on the metal. No the strings, particularly the high e and b strings sound muffled when played open. And when I play a little harder I get kind of a "thunk" or a "spank" which I do not dig. The action is plenty high--a little too high. What is going on here?