Let boomkat give you the rundown:
In striving towards “the merging of visual and sound elements into a new form of intermedia”, the duo forged an exceptional early iteration of rhythmic, electro-acoustic noise which still sounds like it was beamed in from another planet.
The original performance - of which this is a recording, made on June 17th & 18th, 1976 at Fono Play Studios, Milan - involved two camera operators and a wall of video screens displaying close-ups of the performers actions in a symbiotic representation of what the audience was seeing and listening to, attempting to induce synaesthetic sensations and both loosen up, and lose, the primary sonic characteristics of their chosen instruments in the process.
Working to repetitive, techno or raga-like modal phrasings, they use a range of unconventional tools to animate and excite their instruments in ribboning streams of sound. On Air, Christina manipulates her own voice and alto flute whilst Plessi plays a Violoncello with an electric vibrator, resulting what sounds like a pack of wolves circling a wounded buffalo on a bleak high plain at midnight, whereas with Fire they conjure flickering electronic partials and playfully swooping cadence from a Swanee Whistle and contact microphone applied to a ventilator to sound like Clangers on their way to the cheese mines. Likewise in Air Christina’s breaths on an Alto Flute without headpiece are combined with vicious accordion to sound like an astronaut lost in space who receives a deathly distress signal, and the rapid ostinatos of Water elicits comparison with an amplified chorus of hooligan cicadas on their way to a big cup game, when it was actually made using an electronic metronome and water jet on a steel drum.
Most crucially, this isn’t an academic piece, but neither is it trivial; there’s the real sense that Christina and Plessi are in pursuit of the most elusive sounds, and safe to say they’ve located at least some of them within.