Propeller for an aircraft engine comprising means for reducing noise at middle and high frequencies and improving the acoustic perception

A turbomachine for aircraft, comprising two propellers, said propellers being coaxial and arranged one behind the other along an axis of said turbomachine, and said propellers rotating in respective opposite directions, each of said propellers comprising a hub in rotation according to an axis of rotation of the propeller and at least 4 blades distributed around said hub, with each of the blades comprising a blade root by means of which the blade is fixed on said hub of the propeller and an aerodynamic portion extending radially outwardly away from the axis of rotation of the propeller from the root of the blade, with a pitch angle defined for each blade as being the angle that a chord of an aerofoil of the radially inner end of the aerodynamic portion of the blade forms with a plane perpendicular to the axis of rotation of the propeller, wherein in each of said propellers the at least 4 blades comprises a first plurality of blades and a second plurality of blade, each blade in the first plurality of said at least 4 blades uniformly distributed around said hub has a first pitch angle that differs from a second pitch angle of each blade in the second plurality of said at least 4 blades uniformly distributed around said hub wherein adjacent blades of said at least 4 blades are free from engagement along respective aerodynamic portions of said adjacent blades.