Abstract: A gas turbine engine comprises a fan and a turbine section having a first turbine rotor. The first turbine rotor drives a compressor rotor. A gear reduction effects a reduction in the speed of the fan relative to an input speed from a fan drive turbine rotor. The compressor rotor has a number of compressor blades in at least one of a plurality of rows of the compressor rotor. The blades operate at least some of the time at a rotational speed. The number of compressor blades in at least one row and the rotational speed are such that the following formula holds true for at least one row of the compressor rotor: (the number of blades×the rotational speed)/(60 seconds/minute)?5500 Hz; and the rotational speed being in revolutions per minute. A compressor module and a method of designing a gas turbine engine are also disclosed.