After wanting to play for years, I finally bought a soprano uke and dived into the world of ukulele. However, I've been having problems with buzzing and twanging. The sound the uke makes when I play the F chord in particular feels muted and has a "thunk" noise. I suspect it's something in my left hand position that is at fault, but don't know how to correct it. I try to pay attention to "tunneling"my fingers, trying to make sure they don't graze the strings that aren't fretted, but it still sounds off.