The orchestra is, when you think about it, an odd beast: an assortment of technical specialists (their precise deployment customisable depending on the circumstances) whose expertise is in the vibration of skin, string and air. For hundreds of years, its constituent parts grew in number and became more complex in arrangement, shaped by the whim of ever more inventive and demanding composers (especially Beethoven) and the broadening of a professional concert culture. In the 20th century, it seems that the orchestra reaches the apogee of its development, for the symphony orchestra today is much the same as that of the 1910s, when the piano was finally grudgingly accepted into its ranks. Composers today are faced with the same highly variegated, sophisticated ensemble as Stravinsky’s Petrushka. Since the development of the orchestra appears to have plateaued, does this make it now an unevolving museum piece? And does its current state reflect the ideal palette of sounds for a composer to play with, on top of which no other type of sound needs adding? Well, no, in both cases. But the practicalities of performing the repertoire, and thus a healthy concert culture, depend upon a level of consistency within the ensemble. Composers may add various extra layers of sound to an orchestral score- Messiaen’s ondes martenot or John Adams’ samplers- but as a rule the orchestra exists as a compromise between the logistics of live music-making and a Platonic ideal of ‘sound-art’.

The sound of a full orchestra is so common a sense-experience to us that it is easy to overlook the extraordinary complexity and wonderful strangeness of its instruments, themselves the product of generations of honing, refining. The various transpositions of woodwind instruments, and the cohabitation of ‘fixed’ note instruments such as percussion (here extended to include harp and piano) and instruments with access to a more fluid, microtonally inflected pitchspace (most obviously the strings) conspires to create a major tuning headache for all but the finest ensembles, but also results in the unique way an orchestra ‘sings’. It is the delicate balance in which these conflicting tunings are held in check that accounts for the orchestra’s particular harmonic footprint.

Bells, too, have fascinatingly complex harmonic spectra. Their overtones are inharmonic, which is to say that their frequencies cannot be analysed as nice whole multiples of the fundamental frequency, as those of a vibrating string can (though not perfectly). This accounts for the captivating afterglow of the bell, as its initial stroke is transformed ‘into something rich and strange’. Many composers have been inspired by bells, from Stravinsky himself in Les Noces to the spectral analysis of Jonathan Harvey’s Mortuos Plango, Vivos Voco and Julian Anderson’s recent Bell Mass. For Tocco, I turned again to the process of change-ringing, the mathematical process by which bell-ringers compose peals, which can be very complicated or very simple. In a previous piece, Cascabelada for 4 pianos and percussion, this technique was used to generate single pitches, resulting in music that sought to emulate directly the irregular (and yet highly controlled) clanging of a set of bells. Here I was keen for the bells to be a little more oblique. Therefore, the change-ringing method is here used not to determine the melodic movement, but rather the harmony.

To do so, I had to think about how numbers could be used analogously to harmonic movement, and the natural solution came in the form of the circle of fifths, which returns to its starting point after cycling through all twelve notes of the scale. Therefore I chose for my original row the numbers 1-12, with each successive number representing an upward transposition by a perfect fifth. This row is developed according to the simplest change-ringing method, the ‘plain hunt’, in which pairs of numbers swap positions in each successive line:

1 2 3 4 5 6 7 8 9 10 11 12
2 1 4 3 6 5 8 7 10 9 12 11
2 4 1 6 3 8 5 10 7 12 9 11
4 2 6 1 8 3 10 5 12 7 11 9
4 6 2 8 1 10 3 12 5 11 7 9

These chains of numbers determine the sequences of transposition of fragments (chosen freely by me) from a 12-note source chord, the effect being that of objects being viewed from rapidly shifting perspectives. These iterations form the underlying structure of the piece. Consequently, Tocco is by far the most ‘systematised’ music I have ever written, being a conscious attempt to impose a more rigid framework on my music, whilst still allowing for intuition to have the final say: if a sequence of chords resulting from the mathematical pattern doesn’t sound ‘right’, I need not blindly follow it to its conclusion, but might replace it with a different fragment from the source chord, or tinker with the textural or rhythmic detail of the passage to ‘smooth over’ any potential rough edges arising from some harmonic disjuncture. The challenge of solving such compositional quandaries has always appealed to me- they are musical puzzles, and each one might have only satisfactory solution.

Another concern for the piece was that it should provide sufficient textural contrast in its four-minute span. Such a short commission suggested to me (and indeed all the other composers) a fast tempo, since anything slower would not necessarily exhaust itself in time. But I felt that four minutes of uninterrupted virtuosity could sound wearyingly frantic and hyperactive. To that end, I decided to create a tripartite structure with a slower central section, which explores the circle of fifths in more detail. I think (and hope) that this breaking up of the pace of the music creates the illusion of the piece being longer than it actually is!
Tocco represents the summation of many of my recent compositional interests, and, while there are areas that are more successful than others, I am proud of its overall shape and impact. Because I see it as something of a ‘summing up’ of ideas, I suspect (hope?) that my next piece will see an approach very different to anything I have previously attempted.