It was appropriate that the six-day Sydney Festival celebration of J.S. Bach’s life and works should end in death. The Neilson Nutshell was dimmed and a smoky haze pervaded the main hall from which the seating had been removed, to be replaced by ranks of yoga mats.

Looking down from the gallery above, it was hard not to think of bodies laid out in a gymnasium after a disaster. But all disturbing thoughts were put aside when the four Ensemble Apex musicians – violinists Anna Da Silva Chen and Madeleine Jevons, violist Henry Justo and cellist James Morley – filed in and sat themselves down next to a gong and hanging cymbal and tables laid out with glasses of water and various small implements.

The quartet launched into a fragile and elegant arrangement of J.S. Bach’s song Come sweet Death, come blessed rest, with minimal vibrato, the Neilson’s beautiful acoustics highlighting the mellow tone of the strings.

The short piece then faded into an electronic haze before segueing into Italian experimental composer Carla Iannotta’s challenging work Dead Wasps in the Jam-Jar iii for string quartet and electronics. This 12-minute piece requires the players to attach paper clips and various mutes to their instruments to produce effects which wouldn’t come amiss in a soundtrack for a Stanley Kubrick-style horror movie.

Ensemble Apex. Photo © Keith Saunders

It is part of a series which, according to the programme notes, “takes its inspiration from the skeletal structures of Bach’s solo sonatas”. It was hard to for this listener to hear anything relating to Bach – Berio, perhaps – in among the electronic sound effects, sampled vocals and swooping and sliding string figures.

But we did get the old master, untainted, next with a lovely performance of the final Contrapunctus from The Art of Fugue. This was originally programmed to end the evening, halting as it does poignantly at the point where Bach stopped composing, but instead the silence was shattered by the opening screeching threnody Night of the Electric Insects from George Crumb’s Black Angels.

Subtitled “13 images from the dark land”, the avant-garde composer wrote it in 1970 when the Vietnam war was still raging and it reached a wider audience when Kronos Quartet recorded it in 1990.

Crumb uses voices, percussion and bowed goblets of water and a welter of instrumental effects to conjure up various ghostly impressions of war versus spirituality. At one stage the violins and violas are turned upside down and the cellist uses the wooden side of the bow to evoke “sounds of bones”. The God’s music section requires the glass harmonicas, all interspersed with references to Schubert’s Death And The Maiden quartet and the Dies irae played like a ghostly viol consort. Parts are punctuated with snatches of verse by Federico Garcia Lorca, a crashing gong and a bow scraped over a cymbal.

The electronics for this and the Ionnota piece were provided by Benjamin Carey, seated at a console in the gallery at the back of hall.

Black Angels still exudes power and fascination more than 50 years on, and this performance by the young ensemble was jaw-droppingly good.

The concert, which was curated by Ensemble Apex’s Artistic Director Sam Weller, came to an arresting close with the reiteration of the furious Night of the Electric Insects section.

The Saturday night performance was sparsely attended – there were plenty of vacant mats – which was a shame as this was an excellent concert and a worthy ending to a notable festival within a festival.

Limelight subscriptions start from $4 per month, with savings of up to 50% when you subscribe for longer.