The invention concerns a turbine or a micro-blower for a respiratory assistance apparatus comprising an electric motor (1) with a vaned rotor (2) for generating a gas stream； a bellmouth (5) for sucking in gas, such as air, when the vaned rotor (2) is driven in rotation by the electric motor (1)； a volute (3, 4) comprising an internal compartment (10) enclosing the vaned rotor (2) and at least one portion of a discharge conduit (7) conveying the gas delivered by said vaned rotor (2). The bellmouth (5) is arranged on the upper portion of the volute (4), and they together define at least one dead volume (6). According to the invention, said dead volume (6) comprises at least one soundproofing material (11) capable of reducing at least a part of the noise emissions generated by the motor (1) and/or the vaned rotor (2) during the rotation of the vaned rotor (2).
