Practicing resonance is a fundamental technique performed frequently by opera singers. The technique consists of drawing small amounts of air into the lungs and controlling the amount of air released by the lungs. Many opera singers practice the technique by holding a lit candle in front of their mouths while they carry a tune. If practiced correctly, the singer should be able to carry the note without enough air slipping from the lungs to make the flame of the candle flicker or extinguish.
Restricting the diaphragm just prior to taking a deep breath is another technique used by opera singers. Restricting the diaphragm consists of taking a large breath of air just before singing a note and tightening the muscles of the diaphragm as the singer exhales to maximize the amount of air that remains in the lungs as a note is sung. If performed properly, the diaphragm flattens under the pressure of the lungs as the singer inhales, allowing the lungs to expand fully during the course of the note.
Another key technique used by opera singers is posture placement. During the course of a performance, a singer raises her head high, throws her shoulders back and holds her stomach tight to permit the lungs maximum room for expansion. In addition, the singer will often wait until in-between lines to move about the stage so that precious breath is not wasted during the course of movement.
Feather exercises consist of using the breath to manipulate an object to move without using any other parts of the body. Most singers use a feather for the purposes of the exercise due to its lightness and ability to move about. To perform the technique, throw the head back and place a feather on top of your mouth. After taking a deep breath, blow the feather in the air above you using just the air from your lungs as you exhale. This exercise helps to expand the esophagus and trains the lungs to perform on demand.