True about blood pressure measurement is all, except

In the point at which systolic pressure in the aery just exceeds the cuff pressure, a spu of blood passes through with each heabeat and, synchronously with each beat, a tapping sound is heard below the cuff. The cuff pressure at which the sounds are first heard is the systolic pressure. As the cuff pressure is lowered fuher, the sounds become louder, then dull and muffled. These are the sounds of Korotkoff Ref: Ganong's Review of Medical Physiology Twenty-Third Edition Page No:545