Through this Chronophone system Gaumont synchronised sound and film, at the Gaumont Palace in Paris in 1910. The compressed-air amplifier was part of the system and the two gramophones were operated from a common electric motor between them. An air hose goes to each valvebox from the control valve just under the air pressure gauge. Initially the longest film that was synchronised with sound was about 60 metres (playing time of a single Gramophone record). Movies were projected at 16 frames per second. Gaumont solved this problem by having two gramophones operated from the same source so an operator could switch between them in order to achieve an almost continuous soundtrack.