End of the Road Festival, Larmer Tree Gardens, Dorset

Nothing much has changed, down here at the End of the Road. The fairy lights draped over the trees give a more magical sense of perspective; there are framed Victorian photos round the piano in the maze-like gardens, where children, drunken adults or star musicians improvise tunes. There are bigger names in this Americana-rooted festival's fourth year than ever before, attracted, as Neko Case attests on stage, by the feeling that, "It's like someone actually cared that we're doing a show." Whether wandering through strange grottos or watching the bands, rock'n'roll as a disorienting, imaginative, civilising experience remains real here.

It's no coincidence that harmony is a recurring musical theme this year. Brooklyn's Dirty Projectors experiment in time signatures, guitar sounds, and harmonies sounding like sped tape or reversed vinyl grooves, with just enough funk and feeling to reach me. Fleet Foxes' drummer J Tillman is found singing his almost liturgical songs at the back of a tiny tent, where the packed crowd can only hear the slow, occasional notes of his echoing voice when they're close enough to stumble over this bearded young hippie, hunched over his acoustic guitar. It's a more intriguing prospect than Tillman's main band. But Fleet Foxes catch some magic too. Just as a clear night of bright stars is inspiring cosmic thoughts in me, they start a new song about the night sky and our place on the planet. The band's casual chats with the crowd about tea-drinking and clear nerves, despite their success this year, are endearing in a warmer show than their prissy Glastonbury set.

Fleet Foxes' harmonies and sentiments remain too pure for me. Blitzen Trapper hit a sweeter spot when their voices merge, over an easy-going 1970s rock kick that really thrills. And meanwhile, around midnight, there is Josh T Pearson. The great lost talent of this American generation, unheard on record for almost a decade, there is tension, shivering energy and no harmony likely in his lonely voice. He has the beard of a biblical preacher or backwoods gunslinger. Shadows keep settling in a mask over his face, except when his eyes are raised pleading to God. Beginning with U2-style stormy guitar, he rolls out two country songs carved from the form's heart of domestic hurt and fear. He quotes Joy Division's "Love Will Tear Us Apart" on one, and has that band's deep seriousness. When his voice wails, it comes from a deep, desperate place.

A bizarre variety of blues is on offer, too. Bob Log III wears a gold jumpsuit and crash helmet as he implores, "Put your boob in my scotch", during a winningly sleazy display. Sweden's Wildbirds & Peacedrums offer a tribal, twin-drum whomp, while Iowa's William Elliott Whitmore sticks with straight country blues. "The circle was broke before I was born," he sings, of his own hard times, before leaping into a roaring crowd. The young, nervous Scottish folk star Alasdair Roberts simply erases time as he grippingly sings old songs of suffering. Steve Earle does the same with hard luck songs by his Texan mentor Townes Van Zandt, in a comforting statement of community and decent values this crowd understand.

There are disappointments. Beth Jeans Houghton, hyped at the start of the year, seems to be wearing one of the Gardens' roaming peacocks on her head, but is giggling and amateurish. The Duke and the General offer blowhard, over-sung "soul" more than their fine debut album's early 1970s Californian pop sheen.

But there's no room for complaint when I can barely drag myself to The Hold Steady's drunken, sometimes over-dramatic celebration of rock'n'roll itself, because Richmond Fontaine are playing their beautiful losers' songs nearby. I have to tear myself away from the best festival of the year.