I have experienced this just yesterday. Ever since I got my70# bow with incorrect thinner pivotsinstalled and with weight backed off to 63 pounds the bow has had ahollow low tone vibration sound and feel to it. I just figured that was the nature of the beast for mylonger ATA Old Glory. The Tribute was silent. Well after last night, I got the thicker pivots installed and dialed the bow up to 70# and WOW! it is very quiet and no shock, just like the Tribute. Took my 443 grain arrows right up to 288 fps from 270 just by changing out the pivots. Now that should put me up into the 80 ft pounds of KE range.[:-]