The repertoire in which instruments or voices are electronically treated in live performance are mostly of a solo or small ensemble nature. Jonathan Harvey’s From Silence for soprano, six instruments and live electronics has the voice treated with a harmoniser, which transposes the vocal production to several parallel intervals. Cristóbal Halffter’s Planto por las victimas de la violencia uses live electronic transformations of several instruments. It is a process less used in the symphony orchestra because any instrument which is treated requires the use of a microphone. Any other instrument close to the one being treated will also be picked up by the microphone. My own work for large orchestra, Saturn, solves the issue with the inclusion of four soloists set apart from the main orchestra. There are episodes in the work when instruments in the main body of the orchestra are electronically treated. When these sections are completed the related microphones are switched off. Initially, the solo group plays with the full orchestra, but treated by a tape delay system which introduces what has been recorded at a later stage, signalled by the conductor. At the first episode in the work, delays are superimposed on the live performance, requiring exact metronomic alignment with live and recorded playback. For this to work the conductor has to use a ‘silent’ metronome with a flashing light so that a constant tempo of = 100 is sustained to combine both elements of the score with pulse unison.

The work is a celebration of the arrival of Voyager II at Saturn in 1980 with the discovery that the planet had many more satellites than were previously known. With Holst’s ‘Saturn chord’ as the organism for the work, it is a homage to the great composer. The names of the major satellites function as motivations for free variations. ‘Tethys’ involves woodwind multiphonics with specific fingerings to produce the pitches of the written chords exactly, but with the added dimension of ring modulation treatment, which transforms the chords with a wide range of added harmonics (Example 38).

The planet is dark and black, inviting the otherwordly character of the resulting music. While the fingerings for the multiphonics are explicit in producing the required pitches in the untreated chord, the ring modulation adds harmonics which are of uncertain origin.