I really like my MakerFarm printer, but even after tightening belts etc... I'd still have some ringing in the X direction. My theory was that the two screws which are used to attach the belt to the carriage were acting as springs (because attached only at one end). So I made this little part to tweak this mechanism. It goes over the back of the carriage instead of the first nut (it does need a slightly longer M3 screw). This allows the pivot point for the belts to be supported on both ends.
It fixed the (small) amount of ringing I had left in my printer but YMMV. ;-)