Album: Mercury Rev, Snowflake Midnight (V2)

Only a few bands succeed in reinventing themselves even once, and it's hard to think of more than a select few – Pink Floyd, Fleetwood Mac, The Beach Boys, The Grateful Dead – who pulled the trick off twice. OK, The Beatles.

But with the gorgeous Snowflake Midnight, Mercury Rev have done just that, and re-connected with the exploratory impulses that drove their earliest works.

In the beginning, the Rev were an avant-garde outfit on the cusp of art and chaos, capable of brilliance and bullshit; but as with the best free-jazzers, their heights were that much higher. Then, with 1998's glorious Deserter's Songs, the band transformed itself into a visionary precursor of the current US indie boom. But by 2005's The Secret Migration, they were starting to sound a touch precious – and, worse still, short of a decent tune.

They needed to change, and they knew it. Such is apparent from the lyrics throughout Snowflake Midnight – full of images of transformation and metamorphosis, of elemental change and eager curiosity. "Whatever happens now, they say, is whatever we choose," sings Jonathan Donahue amid the bustling percussion, melodion and ghostly chorale of "Dream of a Young Girl as a Flower", which recalls Kate Bush in style and subject matter. Snowflakes are encouraged to "melt... into something bigger than you", a "Runaway Raindrop" prompts reflection on being and becoming, and "Senses on Fire" flare into a chant of "Ready or not, here I come".

The theme of change is borne out in the music, which ingeniously balances opposites – calm and agitation, quiet and loud, soft and strong – in intriguing equilibrium, with gossamer mellotron or string-synth washes and gently cycling keyboard figures in tension with thunderous drums, dramatic piano chords and chugging Krautrock grooves. The most impressive aspect is the way that opposites are yoked together, and arrangements kept in a state of constant flux, with no discernible shifting of gears. A track such as "People Are So Unpredictable" encompasses furtive, undulating keyboards, clamorous drums, minimalist piano repetitions, motorik grooves, massive distortion and breathless trepidation on the way to its shimmering, weightless coda, never staying in one place for more than a few seconds: bearing out its title, it's the same personality, just acting differently.

The same could be said for the album as a whole. If all bands embraced change with the questing spirit displayed by Mercury Rev here, pop would be what it should be – the most dynamic and absorbing art form of all.

Pick of the album:'People Are So Unpredictable', 'Snowflake in a Hot World', 'Butterfly's Wing', 'Senses on Fire', 'Runaway Raindrop'