An acoustic attenuator 20 for an engine booster such as a turbocharger 10 for an engine 4 is disclosed in which the acoustic attenuator 20 includes an attenuator chamber 28 in which is located at least one absorption media 140. The acoustic attenuator 20 is located adjacent an inlet port of the turbocharger 10 so as to attenuate any acoustic pressure waves by dissipative reaction with the absorption media 140 before they have chance to reach other components of a low pressure supply system 50 for the engine 4.