A cable and pulley or guide apparatus for accurately tuning and securing a tunable vibrating membrane on a cylindrical shell by means of a plurality of either fixed-angle pulley or guide assemblies not parallel to the top-bottom axis of the shell, or adjustable-angle pulley or guide assemblies not parallel to the top-bottom axis of the shell, built into or attached to purpose built hoops, attached to hoops with protruding flanges through holes or slots, or attached to a claw or hook apparatus which secures over the edge of annular hoops, through which a cable is laced and fed into the tensioning mechanism(s) to increase or decrease the tension on the cable, thus tensioning the vibrating membrane or heads against the shell, the angles of the pulley or guide assemblies adjustable to conform to the natural angle of the cable traversing the circumference of the shell.