organ and orchestra (3.2+1.2+1.2+1/4331/2timp.3perc.pno/str)
composed in 1977
dedication: to Stephen Plaistow
commissioned by the BBC
published by Novello and Co
first performed at Winchester Cathedral, 31 August 1978 by Gillian Weir with
Bournemouth SO, cond. Del Mar
London Premiere: 8 September 1978, Royal Albert Hall (BBC Proms), same forces
[tape of Prom at BMIC]
For sufficient reasons, pieces of music, like ships and people, must have names. That being so, my choice of a title was governed by the nature of the music I was trying to write, and by the need to discover its proper name. I wanted to write a work in which two complete and complex sound entities, organ and orchestra, would operate together, each on its own terms. Despite attempts during the nineteenth century to create organs which produced sounds analogous to orchestral timbres, the fact remains that, from the point of view of tonal properties, organ and orchestra are polar opposite. It is this essential 'dissonance of timbre' between them which led me to call the work Diaphony, a term used by medieval theorists to indicate elements which sound against one another; this seems to have been their term for what they considered to be harmonic dissonance.
My interest in this medieval term further relates to the origin of the work, which was written with a view to performance in St. Albans Abbey; the association of the organ with religious ceremony, together with the remarkable story of Alban himself, both played their part in the conception of the music. The brief first movement is based on two contrasting ideas, a fanfare-like figure and a pulsating pattern of repeated notes, which gradually interpenetrate one another. After a short silence the second movement begins; this is a set of variations, eighteen in all. Eleven are played by the orchestra and seven by the organ, but in pursuit of the idea of their mutual independence they play them together, not in alternation. This means that the overlapping of differing kinds of music, initiated in the opening movement, is carried a stage further.
The result of this overlapping is twofold; organ and orchestra preserve their variational independence, but the result of their simultaneous activity is heard by the listener as a continuous process of transformation. At the beginning of the movement the individual variation are clearly defined, but as they become mixed together an overall increase of pace turns slow music into an allegro, and the allegro into a scherzo. Here the actual form of the music mirrors the acoustical implication of the title, being an analogy with the phenomenon of combination-tones - the process whereby the union of two different sounds will yield a third.
The abrupt emergence of the cadenza-like final movement from the gradual and cumulative development of the second represents a further extension of the relation between organ and orchestra. This time it is a question of alternation and opposition, since the three so-called Voluntaries played by the organ are interrupted by the orchestra. When this happens, the organ plays patterns of fixed and repeated sonorities which oppose the sound of the orchestra. When the orchestra falls silent, the organ resumes the Voluntary at the point at which it was abandoned. The orchestral music is finally reduced to a single thread, a cello solo which leads to a final statement of the material which was the subject of the variation movement.