“This is the first time we’ve played this song in front of people that aren’t us,” says Lovefoxx, the catsuit-clad lead singer of CSS, before the band launch into Move, from their forthcoming album, Donkey, due out in July, with grinning, hair-shaking joy. On stage as part of MTV’s Spanking New Tour, which promises fans a first chance to hear new music by established bands alongside performances by newer acts, the Brazilian group take visible pleasure in the chance to play something fresh. Lovefoxx has admitted how tired she is of some of their older songs, and it’s hard to blame her. Having released their lo-fi debut, Cansei De Ser Sexy, in 2006, the band have seemingly toured nonstop as the record grew from a cult favourite into a worldwide hit, and many of their singles revolve around sweetly daft sing-along choruses. Tonight, though, the group’s newer songs, many of which attempt a greater lyrical and musical complexity, don’t extract the same ecstatic reaction from the crowd.

It’s not just a lack of familiarity that keeps fans from jumping. Toning down the shoutiness of the vocals challenges Lovefoxx’s voice, and she occasionally struggles to hold the tunes. While older songs such as Meeting Paris Hilton hit on a combination of sexy bass and spiky synths that makes it hard not to shake your hips, new songs lack this alchemy. Ticker-tape bombs, multicoloured balloons and Lovefoxx’s eccentric outfits - including a hat apparently made from grass and bunches of flowers - make for a party atmosphere, but the new music means it doesn’t add up to a carnival.

Support act the Futureheads could tell CSS a thing or two about difficult second albums. Despite doing well with their self-titled debut, the Sunderland four-piece were dropped by their record label after disappointing sales and reviews of 2006’s follow-up, News and Tributes. Songs from their third album, This Is Not the World, which the band release on their own record label, Nul, at the end of this month, show that they’ve stuck with their distinctive combination of twitchy postpunk rhythms and ultra-precise stops, starts and changes of time signature, and prove that the formula still works. A new song, Hard to Bear, comes as close to a ballad as the band have yet got, using stuttering vocals but slower rhythms to describe the end of a relationship, while the subtly interlocking riffs and soaring chorus of Radio Heart, also from the new album, whip the front rows into a sweaty, jumping mass.

The show openers, MGMT, whose much-hyped debut album, Oracular Spectacular, was released in March, come off badly tonight. The gig doubles as the first night of their own UK tour, but whereas on record their tripped-out psychedelia worms its way into your head, here their witty, dreamy lyrics and whirl of synths, strings and guitars blend into a muddy, bass-heavy dirge. The band look almost bored, as do the audience; those who liked the record will get the chance to weigh up the live show when this series of gigs is broadcast on MTV Two between May 30 and June 6.

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