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Alternating Unisons and Octaves

I am hoping someone intimately familiar with Tchaikovsky's orchestral habits may be able to answer this question: Did he sometimes have the cellos and basses alternating between playing in unison and playing in octaves? (I know that he did all sorts of curious things in terms of cross voicings, having the basses cross above the cellos, for example, etc.) An arranger told me this was a "trick" he picked up from Tchaikovsky, yet I myself cannot think of any examples off hand.-

William H. Rosar
The Journal of Film Music

One reason why a composer may alternate unisons and octaves is to avoid notes which fall below the range of one or the other instrument (or section). In the last movement of Symphony No. 4, the cellos and basses begin the main subject in unison, with the basses in a high register. Mid-way through the third measure, the cellos reach their low C and jump up one octave, so that the two sections finish the phrase in octaves.

Now look at the first fff statement of the main subject in the third movement of Symphony No. 6 (m. 229). The cellos and basses play in octaves for most of the first three measures, but in the fourth measure the basses reach their lowest note and play the Eb and D an octave higher, in unison with the cellos.

If you look at the parts for third trombone and tuba, or first and second bassoon, you will find many examples of the same device.

Nicolas Krusek

In addition to overcoming instrumental range limitations as Nicolas Krusek cogently explains, I suspect that there are other reasons as well related to part writing, especially in homophonic chordal passages, such as those involving parallel movement or similar movement, in this instance, to make the bass line stronger and more dynamic by introducing contrary motion where there might be none. For example, instead of a bass line in a given chord progression ascending in whole steps, by alternating unisons and octaves on the bottom, it breaks up the stepwise movement which, in a bass line, is not necessarily desirable, unlike the tradition in melodic writing, where stepwise movement is typically preferable.

If one looks at the beginning of the slow mvt. to the 5th symphony, Tchaikovsky cross voices the cellos and basses in such a way that the basses are often rising or falling an octave, even though the actual bass line in those instances is moving stepwise. A similar procedure can be observed in the last mvt. of the 6th with the opening progression of parallel chords, in which the string parts actually zigzag rather than move in parallel motion downwards, even though the whole texture is moving in parallel motion. There is an old 78 rpm recording in which the strings glide (portamento) between pitches and one can clearly discern their zigzag movement in this passage (I thought it was the old Mengelberg recording, but just now checking, it is not). It would be interesting to determine if this was an innovation of Tchaikovsky's, or something that he learned in studying orchestration (perhaps from the French).-

William H. Rosar

Mr. Rosar refers to an unusual device of orchestration in the opening measures of the Fifth Symphony's slow movement. The double basses and the cellos alternate in providing the bassline, contrary to the usual rules of part-writing. This is an example of a procedure that Tchaikovsky used in various works, where a line in a texture, or even an entire texture, is alternately played by two groups of performers. An illustration of the latter is in the Fourth Symphony's scherzo (starting in measure 365), where strings (playing pizzicato) and wind instruments (woodwinds and horns) switch roles in rapid and regular succession (one beat per group of instruments).

Mr. Rosar could well be correct in suggesting that French music may have provided Tchaikovsky with a starting-point: Berlioz is a possible precursor—see the March to the Scaffold from the Fantastic Symphony (m. 82 onwards). However, it should be emphasised that the Romantic-period usage of this method is an apparently unwitting re-establishment of a device from the medieval period: the so-called 'hocket' (to which the word 'hiccup' is etymologically related), which is described in, e.g., The New Grove Dictionary of Music and Musicians. Berlioz and Tchaikovsky, like other Romantics, are extremely unlikely to have been aware of the provenance of this procedure in the Middle Ages, whose music had long been the domain of scholars, rather than composers.

Henry Zajaczkowski

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