A gas turbine engine includes rotor having a hub, and a plurality of blades extending generally radially from the hub. Each of the blades has an airfoil portion. The airfoil portion has a leading edge and a trailing edge defining a chordwise direction, and a root and a tip defining a spanwise direction. Only a sub-set of the blades has a cutback at at least one of the trailing edge and the leading edge. A method of designing and a method of assembling a rotor having noise reduction properties in a gas turbine engine is also presented.