Rousseau believes strongly that because the saxophone is a wind instrument it is crucial that a warm stream of air be used - "The air is the soul of the sound." “The air stream is very similar to exhaling. Think of 'warm air', similar to fogging a mirror. The mouthpiece creates resistance and prevents the dissipation of the air.”
The concept of warm air is related to the amount of air employed and to its speed; it should not be confused with support of the air stream. He provides a concrete example to help the student learn to achieve a large, warm stream of air - "A small air stream, which is correct for the clarinet, produces a 'sizzle' sound. To produce a large air stream, fill a circle made with the thumb and finger held a couple of inches from the mouth." Warmer air can also be created by changing the direction of the air stream. Blowing down without changing the position of the head is another of Rousseau's techniques to help the student understand the concept.
The embouchure is the connection between player and instrument. Rousseau has described the embouchure as solid and round, like forming the syllable "0" or "00." The lower lip is often too smooth or stretched, whereas it should look to be a little bunched in order to form a cushion for the reed and dampen its vibrations. The corners of the mouth must be well-supported and the feeling of roundness should extend back into the mouth; he recommends the player "think of the inside of the mouth as part of the air column" because "the generation of the tone does not start at the tip of the mouthpiece, but back within the player."