In 1971, John Ike Walton, drummer and banjo player for the 13th Floor Elevators, stayed with me for a couple of months. He had a Fender Artist's Model banjo, which was very similar in construction to a Gibson Mastertone. As we discussed the setup of the instruments, John started thinking out loud. You know, it is possible to tighten a drum head so much that it chokes off the sound. Well, a banjo is just a drum that is being used as a sounding board for your strings.
Every drum has a certain tension where it sounds better.
I'll bet that's true for a banjo, too. What We Did This sounded logical to me. So we took the strings off his banjo, and proceeded to adjust the head tension the same way he adjusted the tension on his drums. As we tapped, we would adjust the bracket, until we found that one frequency where the head seemed to come alive. We started with the pair of brackets at the base of the neck, that is, the pair on either side of the base of the neck.