Abstract: The invention minimizes selected tones present in buzz-saw noise, otherwise known as multiple pure tone noise. This noise arises from the production of unequal shockwaves during the rotation at sonic or supersonic velocities of a bladed rotor, the dimensional characteristics of whose blades are subject to manufacturing tolerances. Minimization of selected buzz-saw noise tones is achieved by arranging the blades around the rotor in a sequence which minimizes selected Fourier coefficients of the shockwave strengths; alternatively, the blades are arranged to minimize selected Fourier coefficients of the dimensional characteristics of the blades, such as thickness, t, stagger angle .theta., and camber. The invention is particularly applicable to the fan propulsors of turbofan aeroengines.