c) Horn (in F). The tone of this instrument is soft, poetical, and full of beauty. In the lower register it is dark and brilliant; round and full in the upper. The middle notes resemble those of the bassoon and the two instruments blend well together. The horn, therefore, serves as a link between the brass and wood-wind. In spite of valves the horn has but little mobility and would seem to produce its tone in a languid and lazy manner.
d) Trombone. Dark and threatening in the deepest register, brilliant and triumphant in the high compass. The piano is full but somewhat heavy, the forte powerful and sonorous. Valve trombones are more mobile than slide trombones, but the latter are certainly to be preferred as regards nobility and equality of sound, the more so from the fact that these instruments are rarely required to perform quick passages, owing to the special character of their tone.
e) Tuba. Thick and rough in quality, less characteristic than the trombone, but valuable for the strength and beauty of its low notes. Like the double bass and double bassoon, the tuba is eminently useful for doubling, an octave lower, the bass of the group to which it belongs. Thanks to its valves, the tuba is fairly flexible.
Table C. Brass group.
These instruments give all chromatic intervals.[A] [B]
Natural sounds are given in white notes. The upper lines indicate the scope of greatest expression.
The group of brass instruments, though uniform in resonance throughout its constituent parts, is not so well adapted to expressive playing (in the exact sense of the word) as the wood-wind group. Nevertheless, a scope of greatest expression may be distinguished in the middle registers. In company with the piccolo and double bassoon it is not given to the small trumpet (E♭-D) and tuba to play with any great amount of expression. The rapid and rhythmical repetition of a note by single tonguing is possible to all members of the brass, but double tonguing can only be done on instruments with a small mouth-piece, trumpets and cornets. These two instruments can execute rapid tremolando without difficulty. The remarks on breathing, in the section devoted to the wood-wind, apply with equal force to the brass.
The use of stopped notes and mutes alters the character of brass tone. Stopped notes can only be employed on trumpets, cornets and horns; the shape of trombones and tubas prevents the hand from being inserted into the bell. Though mutes are applied indiscriminately to all brass instruments in the orchestra, tubas rarely possess them. Stopped and muted notes are similar in quality. On the trumpet, muting a note produces a better tone than stopping it.
In the horn both methods are employed; single notes are stopped in short phrases, muted in longer ones. I do not propose to describe the difference between the two operations in detail, and will leave the reader to acquire the knowledge for himself, and to form an opinion as to its importance from his own personal observation. Sufficient to say that the tone is deadened by both methods, assuming a wild "crackling" character in forte passages, tender and dull in piano. Resonance is greatly reduced, the silvery tone of the instrument so lost and a timbre resembling that of the oboe and Eng. horn is approached. Stopped notes (con sordino) are marked + underneath the note, sometimes followed by
C. Instruments of little sustaining power.
Plucked strings.
When the usual orchestral string quartet (Vns I, Vns II, Violas, 'Cellos, D. basses) does not make use of the bow, but plucks the strings with the finger, it becomes to my mind a new and independent group with its own particular quality of tone. Associated with the harp, which produces sound in a similar manner, I consider it separately under the heading of plucked strings.
Note. In this group may be classed the guitar, zither, balalaïka; instruments plucked with a quill, such as the domra,[9] the mandoline etc., all of which may be used in an orchestra, but have no place in the scope of the present book.
Pizzicato.
Although capable of every degree of power from ff to pp, pizzicato playing has but small range of expression, and is used chiefly as a colour effect. On open strings it is resonant and heavy, on stopped strings shorter and duller; in the high positions it is rather dry and hard.
Table D on page 31 indicates the range in which pizzicato may be used on each stringed instrument.
In the orchestra, pizzicato comes into operation in two distinct ways: a) on single notes, b) on double notes and chords. The fingers of the right hand playing pizz. are far less agile than the bow; pizz. passages therefore can never be performed as quickly as those played arco. Moreover, the speed of pizzicato playing depends upon the thickness of the strings; on the double basses, for instance, it must always be much slower than on the violins.
In pizzicato chords it is better to avoid open strings, which produce a more brilliant tone than of covered strings. Chords of four notes allow of greater freedom and vigour of attack, as there is no danger of accidentally touching a wrong note. Natural harmonics played pizz. create a charming effect; the tone is weak however, and they are chiefly successful on the violoncello.
Harp.
In the orchestra, the harp is almost entirely an harmonic or accompanying instrument. The majority of scores require only one harp part, but in recent times composers have written for two or even three harps, which are sometimes compressed into the one part.
Note. Full orchestras should include three or even four harps. My operas Sadko, The Legend of the Invisible City of Kitesh, and The Golden Cockerel are designed for two harps, Mlada for three.
The special function of the harp lies in the execution of chords, and the florid figures springing from them. As only four notes at the most can be played by each hand, the notes of a chord should be written close together, with not too great a space between one hand and the other. The chords must always be broken (arpeggiato); should the composer wish otherwise he should notify it (non arpeggiato). In the middle and lower octaves the resonance of the strings is slightly prolonged, and dies away gradually. In changes of harmony the player stops the vibration of the strings with his hands, but, in quick modulations, this method is not feasible, and the mixture of one chord with another produces a discordant effect. It follows that more or less rapid figures can only be realised clearly and neatly in the upper register of the harp, where the strings are shorter and harder in tone.
As a general rule, in the whole range of the harp:
only the notes of the first to the fourth octave are used; the extreme notes in both compasses may be employed in special circumstances, and for doubling in octaves.
The harp is essentially a diatonic instrument, since all chromatic passages depend on the manipulation of the pedals. For this reason the harp does not lend itself to rapid modulation, and the orchestrator is advised to bear this fact in mind. But the difficulty may be obviated by using two harps alternately.[10]