Air intake silencing device especially for turbocharged engines or air conditioner and intake circuit with such a device

The noise attenuator consists of a number of annular chambers (6) positioned one after another round a section (5) of the intake pipe (3) and connected to it through apertures (7) to establish a link in the air flow between the pipe and the chambers. The chambers, which are formed by an external section of tubing (9) welded to the pipe at the ends, are connected by calibrated annular passages (8) round the inlet pipe so that surplus air can flow from one chamber to another.