Phase IV opens up somewhere between a 1970s educational nature programme and the ‘book’ sections of The Hitchhiker’s Guide to the Galaxy played straight, so it is apt that its music would initially recall the darker moments from the BBC Radiophonic Workshop: the shimmering waves of Delia Derbyshire’s ‘Blue Veils and Golden Sands’; Malcolm Clarke’s blocks of ring-modulated dissonances for the Dr Who episode ‘The Sea Devils’; and Workshop manager Desmond Briscoe’s spectral driftworks for the soundtrack to the BBC’s original Quatermass and the Pit. So it comes as little surprise that Briscoe himself is credited as having provided ‘additional electronic music’, and much of the electronic realisation has been done by EMS synthesizers enthusiast David Vorhaus, who had worked with Delia Derbyshire on the first White Noise album.
Amid the almost constant bed of electronic drones provided by Vorhaus and Briscoe, the brief fragments of instrumental music are like floating islands of humanity in an increasingly alien world. With its mordant strings, chiming bells and distant brass doubled by distorted guitar, the score could almost be mistaken for a new version of Mahler’s Tenth Symphony, as completed by Scott Walker. Ten years later, the film’s composer, Brian Gascoigne, would provide orchestral arrangements and play keyboards on Walker’s album Climate of Hunter (Gascoigne is an ARP 2600 man), thus beginning a relationship that would continue up to his recent role, crafting sound treatments on Walker’s last studio album, The Drift.
As the film progresses, this latter music becomes ever more a means to encourage the audience to identify, not with the human protagonists, but with the rapidly evolving ants. One scene in particular in which a solitary ant walks solemnly down neat lines of fallen comrades is rendered especially tragic by Gascoigne’s arrangements. If at the start of the film the ants are a symbol for the Soviets, the invading utopian hive mind, by the end, as they struggle heroically to adapt and survive, it is the ants that represent America, one nation under God. For the humans, sound soon becomes itself a weapon, a filtered attack of white noise, not just upon the ant colony, but used equally offensively against the audience.