The higher frequencies gradually taper off in amplitude. The more sinusoidal the opening and closing of the glottis, the weaker the harmonics are. The harmonics have more energy than for modal voicing. Air Stream Mechanisms Pulmonic Egressive Air pushed out from the lungs. Most common mechanism Pulmonic Ingressive Air sucked into the lungs.
Air continues to fill cavity, increasing pressure behind closure.
Air is trapped and compressed by raising the glottis and tensing the pharyngeal wall. Oral closure released and air rushes out. Then glottal closure released. Air is rarified behind glottal closure by lowering larynx. Oral closure is released and air rushes in.