A decade after Fausto Romitelli's death, the Italian composer is still a far from familiar name. Despite a string of successes at numerous European festivals throughout his career, Romitelli's music is rarely performed. The London première of the composer's swansong was long overdue, and it was only right that the work should receive a first-class performance at the hands of the London Sinfonietta.

The music began before the performance itself started, with sporadic electronic pulses resounding through the Queen Elizabeth Hall. Every aspect was calculated to draw the spectator into Romitelli's multi-sensory world; for this piece, the term 'listener' seems insufficient. After all, the composer wanted the piece to be "an experience of total perception... a magma of sounds, shapes and colours". His own notes for the piece describe music in visual terms, and vice versa, casting it as synaesthesia writ large. With surround sound, video screens, electronics and live performers, this piece immerses the audience to almost hallucinatory effect.

Perhaps the best way to describe the work is as a journey into the unconscious. Romitelli plays with your sensory perception, gradually attuning the audience to his particular sonic and visual world: an introductory section establishes the upper and lower limits of the piece, and the harmonic realm in which the piece unfolds. By the time the soprano soloist begins to sing, we are encapsulated within a surreal, sci-fi realm, accustomed to the keening glissandi and thrumming bass guitar. Romitelli begins by holding the audience at a distance, before gradually pulling back the veil as more pointed

Energy is what connects music and light; the more agitated the ensemble, the more animated the video screens. Each screen initially explores light in an abstract manner, with pulsing balls of light: gradually, the images coalesce into identifiable objects, such as microscopic images or discarded rubbish in a rotating cylinder. Sound is projected as light, while the libretto (by Kenka Lènkovich) is constructed around dynamic imagery.

Although Romitelli's score embraces a broad stylistic range, he has a distinctive musical voice. His music bears the traces of the French spectral school (he worked alongside Gérard Grisey and Hugues Dufourt for three years in the 1990s), with resonant bass notes and a brightness to his harmonies. Over the course of the hour-long work, this language is the basis for references to electro-pop, blues (complete with sultry chanteuse) and rock music. However, nothing ever feels out of character: there is a natural progression throughout the piece. Romitelli gradually introduces darker, moodier colours in his orchestration, adding increasingly raw timbres. Eventually, after intensifying all parameters, sensory overload is reached: the screens shut off, the ensemble cease to play, and we are left with a drone.

The soprano Hila Plitmann embraced the theatricality of the work, extracting intense expression from what is an abstract text and changing vocal timbre accordingly. There was something refreshingly relaxed about her technique, especially in the softer, more obviously melodic moments. Conductor André de Ridder effected the transitions smoothly, drawing a tense and dynamic performance from the musicians.

The London Sinfonietta brought off Romitelli’s score with nuance, character and panache, with the brass contributing thrilling virtuoso entries towards the end. They responded to the evolving soundscape effectively, moving from velvety sonorities to violent confrontation. Not only was there an electronics performer as part of the ensemble (initially rendering the ensemble somewhat inaudible, although this improved as the piece progressed), but the performances of the instrumentalists were electronically distorted as well. This chain of refractions and transformations (acoustic sound into electronic sound; sound to image) further envelopes the spectator within a fantasy realm, loosening their grasp on reality. Enigmatic though it may be, it is hard to deny that An Index of Metals is an alluring piece.