Imagine a gig – a proper gig – where everyone gets in for free. Now imagine an event where the fabled guest list (a bit of an oxymoron, granted, when everyone is getting in for free) is not a grubby, well-thumbed wodge of paper, but a shiny, box-fresh iPad. Picture 31 of these gigs, back to back, featuring a diverse array of acts whose common denominator is faintly elusive, all of which are being filmed. If it's Fearne Cotton trailing around all miked up, and everyone else has a bit of plastic on a lanyard round their necks guaranteeing 10 free past performances to download, it must be the iTunes festival – the annual series of gigs helmed by the most powerful music-selling device currently extant.
Watching musical powerbrokers ebb and flow might not be the sexiest-sounding of pastimes. But you don't need to read reams of dry financial news to twig that Apple recently posted profits of £2.1bn for the last quarter. Shiny box-fresh iPads accounted for more of that figure than downloads by Marina and the Diamonds, obviously. But the inescapable conclusion is that iTunes is one of the few music-brokers with the current wherewithal to sponsor a month of free gigs by major artists at a landmark London venue. Music is being done their way now.
And their way is slick. The beautiful Roundhouse has been transformed into one giant TV studio, spectacularly lit so you can see the ironwork holding up the vaulted ceiling. But as with all that is free, there are attendant benefits and costs. Liggers yap their way through both sets. Cameras swoop by like hungry pterodactyls.
The visuals, though, are sharp – as are the performances. Marina Diamandis and her business-like backing band (not, incidentally, the Diamonds – Marina is a solo performer, and the Diamonds are the fans) gleam with a pop starriness that is, thus far, more an act of will than one of record-selling. Her album, The Family Jewels, went top 5 in the UK when it was released in February, but has so far mustered 110,000 sales – solid for a quirky debutante, but not enough to fund the bling that Marina's surname demands. Indeed, she has cardboard-cutout diamonds perched like glasses on her nose for "Shampain", possibly the most conventional of her strident remakes of chart-pop. More endearingly, she sports an extraordinary knitted grey cardie with a bear's head hood for "Mowgli's Road", which, if they were being sold on the merchandise stall, would probably pay back her advance in a trice.
Diamandis has inspired both love – on blogs by Perez Hilton and Kanye West – and disdain for her daffy but gimlet-eyed take on mainstream pop. The hiccupping theatricality of her delivery remains a stumbling block, but there is a tantalising carnivorousness to her lower register tonight that is rarely heard outside pagan ceremonies. More of it would help define her in a marketplace where Florence and her Machine have hoovered up all the credibility. Diamandis's next single, "Oh No!", could really change things, though, taking on Katy Perry for cartoonish impact. It sounds like a hit-in-waiting, with the faint echo of Buggles.
Alison Goldfrapp and her silver-clad backing band arrive onstage through the centre of a giant silver doughnut whose holeyness immediately sets the mind racing. Having popularised human-animal hybridisation onstage around the time of her Supernature album, and having freely exploited the double entendres inherent in rockets on her latest, Head First (ach!), Alison Goldfrapp attracts this sort of licentious interpretation.
Somewhat disappointingly she looks less like a dominatrix Dr Doolittle tonight, and more like a woman who has recently been extricated from a bin full of unwound VHS tapes. Later jackets (neo-Tudor ruffles and fuchsia Honey Monster, respectively) work hard to put things right, but Goldfrapp's image as an imperious visualist takes a dent here.
Goldfrapp's high-impact set ignores their most refined album – 2008's criminally underselling Seventh Tree – in favour of a lubricious discoid shakedown culled from what you might call the rumping, pumping records – Black Cherry, Supernature and Head First. After all, Goldfrapp is credited with kicking off the vogue for glam electronics among young women in search of a pop career.
But even this accessible set takes time to ignite, despite the sublime sound design and the calibre of bass frequencies that can melt cellulite. Marina Diamandis is rumoured to be the kind of synaesthete who assigns colours to notes and numbers, but you can taste every single one of Goldfrapp's delicious notes on your tongue tonight.
Two keytarists take Goldfrapp's current 80s synth influence to amusing extremes on tracks such as "Believer", but Goldfrapp's glam stomps remain their most authoritative medium. "Ooh La La" and "Train" finally whip the crowd into a lather. A concluding "Strict Machine" is so loud and penetrating it sends everyone home having unwittingly enjoyed free liposuction – something for iTunes to ponder for next year, perhaps.
