if you are not already using a tuning peg,try placing a 1/8" dia. peg inside your box towards the back and wedge it about 1" from the back. the further you move the peg forward, the keener the sound .changes in the tone has made a difference several times for me. sandpaper seems to be the only cure for my 102 box tones.i have had mine since 1963 and is the most original sound that i can make.