The Trombone is a very simple but perfect instrument. It consists of a tube bent twice upon itself, ending in a bell, and in the middle section double, so that the two outer portions can slide upon the inner ones.
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Tenor Trombone in its normal position, sounding
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Extended so as to produce
The mouthpiece is held steadily to the player's lips by the left hand, while the right controls the lower segment by more or less extension of the arm. As the usual length of a man's arm is not sufficient for the intervals required by the larger bass instruments, it is, in their case, increased by means of a jointed handle. The same result has also been obtained by doubling the slides, but at a great loss of simplicity in construction. It is therefore obvious that the Trombone alone of all the wind-family has the accuracy and modulative power of stringed instruments. Its notes are not fixed, but made by ear and judgment. It is competent to produce at will a major or minor tone, or any one of the three different semitones. The three Trombones, therefore, with the Trumpet, their natural treble, form the only complete enharmonic wind quartet in the orchestra. And yet no instrument has been so misused and neglected by modern composers and conductors.
The parallel between the Trombone and the Violin family may be carried even farther without loss of correctness; for whereas they have seven 'shifts,' the Trombone has seven 'positions.' These may be easily described as successive elongations of the sounding tube, each of which produces its own harmonic series. The seven positions may be said in a general way to be each a semitone lower than the last. The first is with the slide entirely undrawn. But in the hands of a good player, the length of slide used for each successive position is not the same. By means of a proportional scale, the writer has found that the 2nd, 5th, and 6th shifts are represented by twice 26, or 52; the 3rd and 7th by twice 15, or 30; and the 4th shift by twice 20, or 40. The reason for thus doubling the indications of the scale is the duplicity of the sliding tube, and the doubled length of vibration. The reasons for the variable length of the positions lie too deep in the theory of the scale for our present purpose. They are also, to a certain extent, due to unavoidable imperfections of manufacture, which cause it, for constructive reasons, to vary considerably from a true mathematical figure. But a judicious player, with a sensitive ear, has the remedy in his own power; and the mechanism as well as the mental sensation of Trombone-playing, when thoroughly learned, more nearly approaches that of good voice production than does that of any other instrument. Unfortunately, the quiet smooth legato method of using it is almost a lost art; having been nearly discarded for the coarse blare of the military player. For his use also modern instruments are made of too large a bore.
Like so many other instruments, the Trombone has been made in every key, from A to B♮; and in every octave, from the two-foot to the sixteen-foot. But whereas the former kind has been very properly distanced by the brighter tone of the long small-bored Trumpet, playing in its higher registers; the latter has also been much encroached on by Tubas, Euphoniums, and Ophicleides, which often, though really in the eight-foot octave, are made to produce a spurious effect of depth by largeness of bore and looseness of embouchure.
The three which chiefly survive are the Alto, Tenor, and Bass; usually in the keys of F or E♭, B♭, and G respectively. A bass in F is far more suited to the two upper members of the group, and has been used without break in Germany, notably by Weber in 'Der Freischütz.' It will be sufficient to work out these in detail in a table.
Table of Trombone Positions.
| Alto. | Tenor. | G Bass. | F Bass. | |
| First position | E♭ | B♭ | G | F |
| Second position | D | A | F♯ | E |
| Third position | D♭ | A♭ | F | E♭ |
| Fourth position | C | G | E | D |
| Fifth position | B | F♯ | E♭ | D♭ |
| Sixth position | B♭ | F | D | C |
| Seventh position | A | E | C♯ | B |
It is here seen that the player has in use the equivalent of seven different instruments, either of which can be converted into any other by a single movement of the right arm; though some sequences involve more change, and are consequently of greater difficulty than others.
The harmonic series is the same as that of the Horn and other cupped instruments. The lowest tones or fundamentals are somewhat difficult to produce, and, owing to the long distance of an octave which separates them from the first upper partial tone, are usually termed pedal notes. The available scale therefore commences with the first upper partial, runs without break to the sixth, omits the dissonant seventh harmonic, and may be considered to end with the eighth, though some higher notes are possible, especially on the longer positions.
There is one case, however, where even the harmonic seventh may be employed with wonderful effect, and that is in an unaccompanied quartet of Trombones (reinforced if necessary in the bass or in the octave below by an instrument of fixed pitch, such as a Bass Tuba or Bombardon). This combination, however, is so rare that the writer knows of no
