than about 1 45 u201c low corrected fan tip speed u201d is the actual fan tip speed in ft sec divided by an industry standard temperature correction of tambient deg r 518 7 u0302 0 5 the u201c low corrected fan tip speed u201d as disclosed herein according to one non limiting embodiment is less than about 1150 ft second the use of the gear reduction between the low pressure turbine spool and the fan allows an increase of speed to the low pressure compressor in the past the speed of the low pressure turbine has been somewhat limited in that the fan speed cannot be unduly high the maximum fan speed is at its outer tip and in larger engines the fan diameter is much larger than it may be in lower power engines however a gear reduction may be used to free the designer from compromising low pressure turbine speed in order not to have unduly high fan speeds it has been discovered that a careful design between the number of rotating blades and the rotational speed of the low pressure turbine can be selected to result in noise frequencies that are less sensitive to human hearing that is the number of rotating.