Physical Requirements
Initiating the Sound
Embouchure Formation
Mouthpiece Placement
Some textbooks on teaching brass go into considerable detail about the physical characteristics that need to be considered before a teacher accepts a student. These include shape of the lower and upper jaw, the appearance and alignment of the teeth, and general lip construction. Many of the points made in such books seem logical enough. An excessive overbite in a brass player can cause too much mouthpiece pressure on the upper lip, resulting in poor endurance, narrow range and intonation problems. Irregularities in the formation of the teeth can also result in problems such as teeth digging into the lips. Often, the implication is that potential students with such problems should be rejected.
As in the case of other wind instruments, the sounds produced by trumpets, trombones French horns and the like are the result of a vibrating column of air within the instrument. Some brass players assume that their instruments function as little more than amplifiers of a basic buzzing sound produced by the vibration of the lips. Research dating back to the 1970s, however, has proved this conception wrong [See Arthur Benade "The Physics of Brasses" in The Scientific American, July 1973].
The lips are indeed important, but more for their role in setting in motion a sound wave within the instrument itself than for any sound they may produce on their own. Indeed, in terms of their function the lips are somewhat akin to the reeds used in all other wind instruments except the flute. Air from the lungs passes between the lips, causing them to separate and vibrate rapidly. The opening thus produced is called the lip aperture. In the upper brasses (trumpets, French horn, etc) the upper lip vibrates, while the lower lip acts like a cushion. In the lower brasses (and especially in the case of the tubas) both lips vibrate.
While there are almost as many legitimate embouchure settings as there are successful players, it is nevertheless possible to lay down some general principles about the subject that should prove helpful.
To play higher pitches, the student prevents the faster airstream from blowing the lips out of position by increasing the tension of the lips. This tension is controlled by the muscles at the corners of the lips. The alternative – sharply increasing the pressure of the mouthpiece on the lips – will produce a somewhat similar result, but only at great cost to flexibility and the quality of the tone so produced.
While there can be many embouchure differences among top brass players, it is the similarities rather than the differences that the young student should pay particular attention to. Nobody has said it better than Philip Farkas:
When a student has observed many top players for a while, he becomes distinctly aware that there exists a very definite facial expression while a fine brass player is performing (regardless of the instrument he is playing) which could be referred to as the brass player’s face. This facial expression is a composite of several different individual muscle positions, but the complete expression is very characteristic, and an experienced player could spot a fraud immediately, while glancing through a group of photographs of fine professional players…His jaw will be thrust out moderately, giving even the most chinless player a rather aggressive look. The cheeks will be taut as when one smiles, with perhaps a “parenthesis mark” around the corner of each side of the mouth. Yet, when we study the mouth itself, we see that, in spite of the smiling appearance of the cheeks, the mouth is slightly puckered and not stretched into a smile. The chin will be pulled down and the muscles at either side will be quite prominent, resulting in a “U”-shaped cavity whose base is just above the point of the chin. There is an indication, although sometimes hard to define that the jaw, besides having a forward thrust, is being held open so that there is a good clearance between the upper and lower front teeth [Philip Farkas The Art of Brass Playing, Wind Music, New York, 1989, page 19]
It is generally agreed that the mouthpiece should ideally be placed in the horizontal centre of the lips, not off to the left or right. This is not critical, however. Many successful players play slightly off centre as a result of the shape of their teeth. There are various opinions about vertical placement. For many years, trumpet and cornet players were told that they should have two-thirds of the mouthpiece on the lower lip and one-third on the upper lip. Some teachers allowed this to vary slightly with each player depending on such variables as lip thickness and the shape of the teeth. If the upper lip was fuller, for example, the mouthpiece was permitted to be positioned slightly higher. Nowadays, however, many trumpet players favor an equal proportion of upper and lower lip in the mouthpiece.
Trombone and euphonium players tend to place the mouthpiece in such a way that it covers more of the upper than the lower lip. However, there is less consensus here among fine performers than in the case of French horn players. Tuba players go even further, often placing the mouthpiece as high on the upper lip as possible. Even so, precise mouthpiece placement seems less critical on the tuba than it is on instruments with smaller mouthpieces such as the trumpet and the horn.