The tuba became part of the brass section for large symphonic orchestration during the last decades of the nineteenth century. It supplanted the now obsolete ophicleide as the lowest-pitched brass instrument. In tone quality, mouthpiece, and bore, the tuba may be considered as a super-bass cornet although it embodies some tonal characteristics of the horn and the trumpet. Its position in the brass choir is analogous to the contrabasses in the string section.

Considerable confusion exists concerning the size and pitch of tubas upon which the orchestrator can rely. The possible, but not probable, ones include those in Bb, F, Eb, C, and BBb. Although a choice of tubas may be practicable for a few players in major symphony orchestras, no such choice exists for the vast majority of players in the secondary orchestras of this country. The reason for limiting a preference for Eb and BBb instruments is both practical and economic.

A large number of players of this cumbersome and expensive instrument are frequently recruited from bands where these tubas are standard. Of the two, the one in Eb is most frequently available. Sousaphones, with their rearranged bell positions, are strictly band instruments and should not be considered for orchestration. Tubas are equipped with a set of valves or rotary pistons which change fundamentals and harmonic series in much the same manner as for other valve instruments. Although four-valve models with a slightly extended range exist, the three-valve instrument is standard for the great majority of orchestras.

The range difference of a diminished fourth between the Eb and BBb tubas is a major consideration in writing for them. The same words of caution directed toward the writing for three trombones apply equally well to when they are combined with a tuba. The lowest tones of a BBb tuba have to be either omitted or inverted if played on an Eb instrument. If the latter expedient is resorted to, chord positions become dislocated, as indicated in Fig. B-12.

The low register can be controlled reasonably well at all dynamic levels, but the higher tones with strong dynamics tend to be strident with an all-engulfing tonal power.

Muted tubas are not generally practicable. Although they are standard for major orchestras, the players in most secondary orchestras rarely have mutes available. Few scores call for them and they are cumbersome at best. The orchestrator must be prepared for this eventuality when writing for muted tuba and trombones. Although four-part writing for this combination can be effective as a special coloristic device, an unmuted tuba with muted trombones would resemble the bellow of a giant struggling with the cries of pygmies.

Phrase markings here follow the same general pattern as for the other brass instruments. Bright staccato notes are the closest brass approach to the string pizzicato. Accented attacks are good if confined to comparatively short sections. All tonguing styles are playable but with some sluggishness to be noted in low registers having rapid articulation.

Cimbasso

The Cimbasso, often mistaken as a mere member of the tuba family, holds a unique position in the orchestral brass section. Originating in 19th-century Italy, the Cimbasso is characterized by its distinctively mellow and rich timbre, which bridges the tonal gap between the trombone and the tuba. Unlike the tuba, the Cimbasso employs a forward-facing bell and a valve system, typically with three to six valves, which facilitates a nimble execution of rapid passages. Its tonal range extends from the deep depths of the bass register up to the middle trombone range, making it an invaluable instrument for providing robust bass lines in Verdi operas and later, in film scores to accentuate dramatic moments. When orchestrating for the Cimbasso, it's essential to understand its unique voice and capabilities, ensuring it's not merely relegated to doubling parts but is given opportunities to shine in its own right.