I’ve long been interested in the extension of instrumental resources by electronic means, so when the Equale Quintet invited me to write a piece for them I decided to write in a part for a sixth player controlling a range of devices which would extend the sound of the five brass instruments. The title Equalisation is a slightly ironic reference to the technique, often used in rock music recording, of filtering a sound in certain ways to heighten its effect. Officially, the filtering is simply meant to make the output as equal to the input as possible, but in fact the natural sound of the instruments is often changed quite radically, and indeed, creatively.
In my piece I use two main devices to extend the range of the brass instruments. One is a digital delay line which can be used to create an artificial acoustic, from that of a small bathroom to something like the Grand Canyon. The opening horn solo gets its feeling of spaciousness from the slowly repeating electronic echoes which surround the sound. The delay line also has the means of storing little samples of sound which can then be made to play back, repeating over and over like a tape loop. The loop can then be transposed in continuous glissandos or even in discreet steps throughout several octave leaps, as happens in the middle of the piece.
The second main device I use in Equalisation is a pitch transposer, with which I can add a parallel part to the live music at any interval between an octave below the original to a perfect fifth above. This can be heard very clearly at the beginning of the fast central section of the piece. Here the two trumpets swap short phrases and the transposer can be heard adding parallel intervals to their music, first at a semitone’s distance then a tone, then finally at a minor third, at which point all the other instruments join in, similarly doubled at the minor-third below.
It’s no coincidence that these intervals are prominent in the piece. Together with the descending fifth, they are present in the very opening bars, and are stressed again in the subsequent horn solo. In fact they are prominent intervals in the natural harmonic series and it’s on this series that the harmonic structure of the whole piece is based.
In both Sonata and Equalisation, and indeed in all of my works like Mareas, Driftwood Cortege and The Transistor Radio of Saint Narcissus, I’ve been trying to create a coherent but flexible musical language in which consonant and dissonant intervals are given equal value. I think music today has reached a kind of plateau: almost anything is possible. But it still behoves the composer to forge a coherent expressive language out of all this multiplicity. In Equalisation and Sonata, I have attempted to find a language which is simple but which can articulate wide-ranging musical processes when necessary. What matters is not the means used, whether technological or traditional – in itself a distinction which should never have to be made – but the sonorous results.
©1983 Tim Souster
‘The most ambitious and substantial work was Tim Souster’s Equalisation, complex in the means emplyed with all the instruments wired for sound and the composer at a central control panel, mixing, modulating, delaying and redistributing sounds through strereophonic speakers and helpfully adding cathedral-like resonance to the dry Purcell Room acoustic. Fortunately the basic material is strongly designed to stand up to drastic transformations, while the production and ordering of sounds and their later treatments all appear as parts of a single compositional process.’
Hugo Cole, The Guardian, 8 December 1980
‘’…Nimbus have just reissued on CD a very collectable recording from the 1980s of music by a composer who used to be thought of as Stockhausen’s UK representative. In fact, Tim Souster doesn’t sound a bit like Stockhausen, so thoroughly has he absorbed Stockhausen’s sound revolution into his own outwardly much more traditional-sounding work. Equalisation for Brass Quintet and Live Electronics is a minor classic…’
Richard Osborne, The Oldie, 5 March 1993
‘As the quintet dwells on a gradually slowing tape loop of its own making in the most potent sequence, we are left with the impression of Souster as one of the most strenuous, most accessible and least didactic of Britain’s younger composers.’
Mike Hutchinson, Hampstead and Highgate Gazette, 10 June 1983
