It’s sounds like the first half of a joke: what happened when a famed Greek lute player met a post-rock drummer from Melbourne? But the answer is Xylouris White, a musical collaboration between lutenist George Xylouris and former Dirty Three bandmember, Jim White.

Xylouris hails from the Greek island of Crete, is son to famed singer and lyra player Psarantonis, and spent eight years in Melbourne. White’s musical associations are no less impressive: recalling first seeing him play, PJ Harvey was “completely mesmerised by his fluidity ... he was like a voice, or a dancer, or a painter.”

Great collaborations should have the same chemistry as that between best friends: there is laughter, intimacy and that feeling that each person is somehow face-to-face with a version of themselves. Playing Sydney festival’s romantic Spiegeltent, before they embark on a world tour, Xylouris White felt less like a band and more like dance partners. White on the drums wriggled away in his seat with a strange sensuousness, his arm moving dramatically into the air before striking the snare. His eyes often locked with Xylouris who sang and played his lute with acute sensitivity.

The pair spoke little throughout their 70 minute performance – rarely calling out song names, so apologies for their absence here. Much of their music felt like extended jams – a road trip with no map. The music hit points, rather than destinations, with slinky, playful intros and delicate musical motifs building in intensity and coming galloping home in a barrage of drums and hard strumming.

At times the seated arrangement felt stifling and the audience (with the exception of one woman’s “bravos!”) too starchy for such arousing and at times chaotic music. This transcendental folk, deconstructed by the volatile rhythms of post-rock, demands to be danced to, and when the music hit the loud and fast end of the spectrum – an all-out head-banging mosh.

If this pair of middle-aged, curly haired, musical brothers from opposite points of the globe bring to the table different qualities, it’s impossible to delineate who is bringing what, so in tune are they to feeding and complementing each other’s impulses. Theirs is a true conversation – and neither dominates.

Xylouris White play Hobart and Melbourne before embarking on a world tour

• Sydney festival 2015 runs from 8 to 26 January at venues citywide. Find all Guardian Australia’s coverage here