In past articles I’ve mentioned that the most prevalent problem I’ve encountered when hearing people play is the inability to start notes correctly. When I say correctly, I mean for a note to start instantly, and at full volume and resonance without an accent or bulge. To me there is nothing more basic than this aspect of playing, because as they say, “you only get one chance to make a first impression.” Furthermore, the manner in which a note starts will completely determine the quality of the sound of that note. A note that starts with a slow, lazy airstream will cause the player to push with another part of the body in the middle of the note to make up for the fact that not enough energy was used to start the note, and THIS RUINS THE SOUND.
I have recently thought of an analogy that might help visualize the action that needs to take place to start a note correctly, and therefore produce the best sound someone is capable of producing. I like to think of the point in the embouchure where the tongue strikes the teeth as a door which opens and closes when articulating separate notes. As an example, take a series of articulated quarter-notes, played at a piano dynamic, which everyone seems to have trouble with. (the simplest things are always the most difficult, right?) I visualize a series of doors which must be opened by means of the air touching them. The first one opens the door, which is closed by the tongue sealing the aperture for a millisecond. The tongue retreats (as Arban says,) letting the pent-up air escape with enough velocity to get the sound to speak fully resonant and instantly. The succeeding quarter-notes are a series of doors that must be opened by the air simply touching them. If you wanted to visualize this in a written form, imagine a vertical line (the door) followed by a diminuendo that went right up to another vertical line, followed by a diminuendo that went right up to a vertical line, and on and on. The touch of the air to the door opens that door, which is accomplished by a retreat of the tongue, and a suitable amount of pressure built up in the mouth to propel the air forward to the next door, hence the shape of the diminuendo. How much pressure is correct? Enough to start the note with energy and a GREAT SOUND. The great sound is produced because the air started cleanly and with good velocity, which allowed the body to stay completely relaxed, which is the secret to maximum resonance. In other words, all actions are performed from the chin up, and nothing from below.