Abstract: A device is provided for producing an acoustic signal in a liquid medium. The device includes a pneumatic chamber to contain a compressed gas volume, at least one pneumatic exhaust port allowing the compressed gas volume to be released out of the pneumatic chamber, and a shuttle movable along a translational axis during an opening phase, between two positions: a closed position in which the compressed gas volume is enclosed within the pneumatic chamber, and an open position in which the compressed gas volume is released out of the pneumatic chamber through the pneumatic exhaust port, to produce the acoustic signal in the liquid medium. A hydraulic brake is used to brake the shuttle during the opening phase. The hydraulic brake includes a hydraulic chamber and having a hydraulic exhaust area of a hydraulic volume out of the hydraulic chamber, and includes a control for controlling the acoustic signal.

Abstract: Method, source and shuttle configured to generate acoustic waves under water. The shuttle includes a firing piston closing a firing chamber and contributing to holding the compressed gas, and a transitional region connected to the firing piston. The firing chamber and the transitional region define a most restrictive area through which the compressed gas is released toward the at least one exhaust port, the most restrictive area is substantially smooth while the movable shuttle moves toward the open position, and a profile of the transitional region is selected to reduce a high-frequency content of the acoustic waves.

Abstract: Method, source and shuttle configured to generate acoustic waves under water. The shuttle includes a firing piston closing a firing chamber and contributing to holding the compressed gas, and a transitional region connected to the firing piston. The firing chamber and the transitional region define a most restrictive area through which the compressed gas is released toward the at least one exhaust port, the most restrictive area is substantially smooth while the movable shuttle moves toward the open position, and a profile of the transitional region is selected to reduce a high-frequency content of the acoustic waves.

Abstract: A device is provided for producing an acoustic signal in a liquid medium. The device includes a pneumatic chamber to contain a compressed gas volume, at least one pneumatic exhaust port allowing the compressed gas volume to be released out of the pneumatic chamber, and a shuttle movable along a translational axis during an opening phase, between two positions: a closed position in which the compressed gas volume is enclosed within the pneumatic chamber, and an open position in which the compressed gas volume is released out of the pneumatic chamber through the pneumatic exhaust port, to produce the acoustic signal in the liquid medium. A hydraulic brake is used to brake the shuttle during the opening phase. The hydraulic brake includes a hydraulic chamber and having a hydraulic exhaust area of a hydraulic volume out of the hydraulic chamber, and includes a control for controlling the acoustic signal.