The octobass is an extremely large bowed string instrument, standing at approximately 3.48 meters (11.4 feet) tall. Invented by Jean-Baptiste Vuillaume in 1850, it is essentially a massive version of the double bass. Because of its height and the thickness of its strings, it is impossible to play with standard fingerings. Instead, the player stands on a built-in platform and operates a complex system of foot pedals and hand levers that actuate mechanical 'fingers' to press the strings against the fingerboard. It has three strings tuned to C, G, and C, with the lowest C note reaching 16.35 Hz—a frequency so low it is at the very limit of human hearing and is often felt as a physical vibration rather than heard as a pitch. Only a few original specimens exist, but modern replicas are occasionally used in orchestras to provide an earth-shaking bass foundation.