angled at approximately 45 degrees using fillets 29 in this way the steps 28 are reinforced such that there are relatively abrupt transitions between the regions 26 for tonal quality but there is a relatively small likelihood of stress cracking at the edges and comers of the steps 28 in addition in this embodiment there is the built up terminal region 26 d adjacent the non batter end 16 of the shell 12 this region 26 d is the shortest region 26 of the shell 12 and adds structural support to the non batter end 16 of the drum shell 12 also in this embodiment maple plies 24 each of approximately 0 0275 inches thick are laminated into a generally cylindrical structure of 3 plies to form the basic drum shell 12 the plies 24 of the reinforcement structure 22 are then bonded to the inside of the shell 12 to increase the thickness and strength according to the number of plies 24 added as a retrofit to an existing acoustical drum not shown an appropriate staged bridge reinforcement structure 22 can be bonded to the inside of the drum shell alternatively on a drum shell having two batter ends there could be.