Abstract: Drums have a truncated spherical sidewall section formed integrally with a truncated conical sidewall section. The spherical section is one-half to four-fifths the length of the drum body and it curves about a point located 20% to 40% of the distance between the ends of the drum body. The conical section slopes inward 30.degree. to 40.degree. from vertical. A cylindrical sidewall section extends between the spherical section and the end of the drum. A drum head is stretched across an end of the drum body by tightening bolts which extend through slots in a hoop surrounding the head. The bolts have threaded ends which are received in tapped rods rotatably mounted in the curled ends of sheet elements. The bolts pivot about an axis tangential to the drum body. Radially extending portions of the hoop have bent edges adjacent the bolt heads. The slots are formed in portions of the hoop which project toward the end of the drum.

Abstract: Drums have downward and integrally continuously joined truncated conical walls of 3.degree. and then 30.degree. angles. A drum skin is stretched across a large open end and a brace is connected to a smaller open end. A slide moves downward on the brace as controlled by a screw jack, and cables stretched by the slide across idler pulleys on the body pull down a rim to tighten the drum head and tune the drum.