The edge of the hole acts the same way as the edge of a fipple with air first going into the flute, then building up pressure to make the flow go out. The size of the hole affects the shape of the wav...The edge of the hole acts the same way as the edge of a fipple with air first going into the flute, then building up pressure to make the flow go out. The size of the hole affects the shape of the wave inside the tube which changes the overtones that are present. Not shown in the cross section diagram of the flute is the cork which provides an adjustable end to the left of the mouth (or embouchure) hole of the flue.
