An hourglass transducer including a longitudinal driver, a shell, and a pair of endcaps is provided. The driver drives the transducer. The pair of endcaps is attached to ends of the driver and cap the shell enclosing the transducer. The shell includes a first shell end, a second shell end, and a pleated geometry. The first shell end and second shell end are structured with circular cross sections. The pleated geometry is between the first shell end and the second shell end. A perimeter of the pleated geometry is the same as perimeters of the circular cross sections of the first shell end and the second shell end.