On the closing day of the SoundState Festival at Queen Elizabeth Hall, the Aurora Orchestra was the machinery supporting an eclectic group of instruments, soloists and textures. “Songs from the Road” offered a look at many forms of transformation and migration.

A Norwegian folk song, known in Appalachia and the larger English-speaking world as The Two Sisters, migrated through the centuries until it lay in the hands of Nico Muhly alongside his collaborator, American folk musician Sam Amidon. The first half, long, languorous and enveloping in the best senses, gave us the transformation story of one strange and disturbing song – a ‘murder ballad’ – in which one sister pushes the other into the river so that she may marry her intended; the miller makes a self-playing harp out of the drowned girl’s bones and golden hair; the killer sister and the miller are eventually killed. It was accompanied by captivating projected animation work behind the orchestra, the work of animator Ola Szmida, which laid out the main episodes in the story, side-by-side.

It is typically eerie and disturbing fare for an ancient folk song, and its transformative journey began with a lyrical arrangement by Iain Farrington, full of blissful harp and Jennifer Johnston’s sensitive, delicate mezzo-soprano. This line was picked up again in another arrangement by Farrington, this time picking the metamorphosis up in a Northumbrian version renamed The Miller and the King’s Daughter. Folk music’s ancient and unfathomably wise-sounding beauty was again given a full orchestral, harp and soprano-laden treatment, by no means overlaying or crowding but carving out a beautiful, richly-textured territory for the song to sound in. Johnston and the orchestra then moved seamlessly into a rendition of Mahler’s Lieder eines fahrenden Gesellen, full of tension and grace, an interlude of surety and warmth.

The orchestral section of the evening then came to an end as Amidon and Muhly took to the microphone/guitar/banjo and the piano respectively. Amidon, a curly-haired and unassuming performer with an infectiously attractive voice and suitably unpretentious delivery, then introduced another transformation of the ballad, Scottish this time, where it became The Swan Swims and is apparently counted as one of the “muckle sangs”, long narrative songs. Under a gently fingerpicked tune initially trotted out on Amidon’s banjo, the Aurora Orchestra swelled and rolled (as the changed title suggests) a far more tranquil version of the story, at least on the outside.

It was a mesmerising melding of orchestral and folk textures that was carried further in Amidon’s performance of Saro, a similarly well-disseminated standard of what we now largely label as American folk music, though, as this first half impressively showed, the European origins of this music has featured pathological alteration and transformation, though maintaining an unalterable core which eventually crossed the Atlantic to be turned and tossed again. Muhly’s The Only Tune, composed in 2007 for Amidon, was the fourth and final transformation of The Two Sisters; an ambitiously compressed, varied treatment. Amidon’s renditions of the words, scored in repeating, fragmentary bursts, echoed the world of Samuel Beckett, giving the audience an experience of gradual descent into a strange world with occasional moments of dazzling illumination. The music shimmered, broke, bent and realigned itself throughout 20 minutes of a hugely impressive work that communicated both the inevitable and timeless core of a folk tradition and its beautiful but dark transformations.

The second half consisted of another epically-minded piece: Where We Lost Our Shadows, a collaboration between composer Du Yun and filmmaker Khaled Jarrar. Intercuts of Jarrar’s filmed record of his journey to Western Europe alongside Syrian refugees moved into – and at moments took the place of – Du Yun’s swashing palette of sounds. Jarrar’s film featured only young people: visibly hopeful, living on the street, at a railway station, on the move, in the dark. It was strong footage, sometimes well-placed, but sometimes at odds, with Du Yun’s score, whose orchestral and tonal world was decidedly abrasive and serially-minded, but mostly undistinguished.

The main musical joys were twofold: raga singer Ali Sethi, whose beautiful vocal lines eventually interlaced with those of Johnston’s western tradition, leading us toward a deeply affecting conclusion; and the percussion pyrotechnics of Shayna Dunkelman, including one toe-clenchingly thrilling solo mid-piece. The integration of the rippling sounds of ‘emergency blanket’ into the aural scape of the piece also provided chilling resonances that echoed down at both the start and the conclusion of the work. Despite some disappointment, the ambitious interweave of instruments, video and voice in Where We Lost Our Shadows was another meaningful journey in music and deep feeling. Alongside the beauty of the concert’s first half wanderings, there was enough to be appreciating and wondering at for a good while.