How Embouchure Works
The trumpet embouchure properly functions as a balance between two opposing muscle groups. On the one hand, the orbicularis oris is a circular muscle that surrounds the mouth; when we contract this muscle, the lips pucker like those of a goldfish. On the other hand, we have the collection of muscles controlling the cheeks and chin; when we contract this group of muscles, the lips pull back in a smile or turn downward in a frown. An efficient embouchure balances these sets of muscles: the inward motion of the orbicularis oris counteracts the outward motion of the other facial muscles, with the result that the corners of the mouth, where these forces intersect, remain stationary (brass players refer to this stasis as “firming the corners”). If the corners are firm, the lips (particularly the top lip) will be able to respond to a moving airstream with vibration. This principle is analogous to the strings on a violin, which must be fastened at either end before we can expect them to produce sound at the touch of a bow.
What Can Go Wrong?
Some trumpet players utilize one muscle group to the exclusion of the other, with the result that the corners don’t stay in one place. This inconsistency of corners creates just as much confusion for the trumpet player as if the pegs on a violin were to arbitrarily tighten or loosen during a performance. It is usually possible to identify this type of problem by watching the corners as the trumpet player ascends across a two-octave scale. A player whose orbicularis oris is stronger than the other muscles will pull the corners inward as s/he moves beyond a comfortable range. A player who “smiles” when s/he plays has facial muscles with a stronger pull than that of the orbicularis oris. It is worth noting that all trumpet players have corners which flex across changes in register, but the corners should never move laterally. The most obvious symptom of an inefficient embouchure is, of course, a deterioration in the sound of the upper register.
It is important to remember that the corners are responding to the muscles that are acting upon them. It may be possible for a beginning trumpet player, whose muscles have not really developed to play the instrument, to keep the corners stationary by sheer willpower (i.e. looking in a mirror, trying to keep the corners from moving). Once a player’s habits are established, however, the muscles will strengthen accordingly and from that point established patterns will be difficult to change.
Most (not all) embouchure problems result from one of two root causes:
- The mouthpiece is not in the center of the lips.
- The trumpet player has been repeatedly hitting notes that are too high for the embouchure to support.
Once the orbicularis oris and other opposing muscles have learned to coordinate in a particular way, they will most likely continue to work in that manner until we change a variable that will require a different balance. In other words, we can’t correct an imbalance by simply training one muscle group to the exclusion of the other. For this reason, embouchure problems are easy to prevent and very difficult to correct. The best solution is to monitor students within their first two years of playing to make sure that their mouthpieces stay centralized and that the notes they are playing fall within a comfortable register. Please see the page about range development for information regarding this second point.
Where Should the Mouthpiece Go?
The mouthpiece should rest on a portion of the embouchure that is basically in the middle of the mouth. We need the mouthpiece to be vertically centralized because this placement optimizes the top lip to vibrate at the frequencies that the trumpet is required to play. We need it to be laterally centralized because the air will pass most naturally through the middle of the lips and because this location will cause muscles on opposite sides of the face to develop in balance with one another. Most players set the mouthpiece slightly to the left or right to compensate for crooked teeth, and this is not an issue if the mouthpiece is still basically in line with the incisors.
A substantial overbite or underbite can have an impact on mouthpiece placement, especially in terms of vertical alignment. Fortunately orthodontists have a tendency to correct severe overbites; unfortunately most trumpet players have to establish the habit of mouthpiece placement well before their teeth are ready for braces. It is important to monitor beginners to make sure that their mouthpieces do not slip out of a centralized position, especially within the first two years.
About Mouthpiece Pressure
Mouthpiece pressure becomes problematic both when there is too much of it and also when there is not enough of it. It is possible to damage the orbicularis oris by pressing too hard against the face, and for this reason, excessive mouthpiece pressure should absolutely be avoided. However, it is also true that wind is passing out of the aperture and into the mouthpiece, and there are only two ways to ensure that this wind is used to create a standing sound wave in the trumpet instead of leaking out into the room: by using pressure to seal the mouthpiece against the lips or by focusing the tissues around the aperture to such a degree that the air can only enter the trumpet. I believe this second method (using internal tension to eliminate external pressure) is counter-productive at best, not least because lip tissue needs to vibrate as freely as possible in order to produce maximum resonance. I would instead argue that maximum lip vibration is facilitated not by increasing or decreasing the mouthpiece pressure but by allowing for consistent pressure. The body will adapt to a force that is consistent, especially if this force is counteracted by the opposing pressure of the air entering the instrument. It will not adapt to the sudden pressure exerted by a player who chooses to press down only when it is time to play above the staff.