English semi-opera is a strange beast. We have spoken narration, rather than singing characters, to explain the plot as it unfolds; music then serves to embellish key moments of that spoken plot, whether we have reached a battle scene, a pastoral interlude, or a magical disturbance. In genre terms, this shape can remind us of Provokiev’s Peter and the Wolf, a story broken up and illustrated by music: and, once you settle into it, the shuttling rhythm between music and story is surprisingly and undeniably charming, constantly provoking the imagination and beguiling the ear by turns.

Purcell’s writing, more than two centuries before sound reached a cinema, sounds astonishingly cinematic: he depicts an army preparing for war through a rich pageant of visual images, from glittering harness and impatient horses to fervent, poignant farewells amid bustling camaraderie. When song, and Dryden’s words, are eventually added to the score, they whisk us straight into the province of the other: Arthur’s Saxon enemies, magical spirits, actors (as we see a royal entertainment inside a royal entertainment), and the wider community of Arthur’s court all get a chance to sing, but the principal characters themselves (the young King Arthur and his blind beloved, the Cornish princess Emmeline) never leave the printed page, their love perhaps too intense and private for such direct expression.

It’s a work self-consciously soaked in the courtly atmosphere of a much earlier era, yet taking every imaginative opportunity to entertain its audience: any excuse for a nymph here, or a shepherd there, and Dryden will quickly think up a reason for them to sing for us before the plot moves on to the next bewildering scenario (his libretto strays far from the Arthurian legends we already know, possibly to create a political allegory of the 1679-81 Exclusion Crisis, so as the rightful King Arthur and the Saxon Oswald battle for Emmeline and the throne, the British were disputing whether a Catholic or Protestant should be the next Royal heir).

Vox Luminis’ residency at this year’s Aldeburgh Festival, having begun with Bach and moved on to a mixed programme of Tallis, Byrd, White, Morley, Purcell and Britten, culminated in an infectiously joyous King Arthur, directed with skill by Vox Luminis’ own Lionel Meunier. With the orchestra on stage, this was nevertheless much more than a concert performance, fully acted by singers who used the whole performance space dynamically from scene to scene, and customised their simple, contemporary singing clothes to suit each passing character (monsters and gods go barefoot; when winter strikes, singers huddle under scarves and shared blankets; Love trails a red chiffon scarf through the air to break winter’s evil spell). As the singers’ warm vocal colours explored the richness of Snape’s acoustic, in an atmosphere of gloriously secure, skilful musicianship (with some musicians playing several different period instruments), the genre-busting strangeness of it all just added to the fun. Their air of virtuoso confidence gives Vox Luminis the chance to push each performance further in the game of imagination: we do not only get great singing, but clever touches of humour too, even in their entrances and exits.

Apart from King Arthur’s several spectacular choruses, which seem ideally suited to Vox Luminis’ smooth, penetrating and springy sound, we had standout solo contributions from Stefanie True, Sophie Junker and Zsuzsi Tóth in particular. Tóth’s spellbinding Venus cast an extra layer of awed silence over the audience as everyone listened slightly more intensely to her clean, lyrical and beautifully controlled soprano. Tomas Kral made a muscular, malevolent Grimbald, his huge voice sometimes working itself into a final shout which I suspect was a deliberate part of the performance plan; later, he was a honey-toned Aeolus. Stefanie True’s sprightly and appealing Philidel made a lovely foil to Grimbald, while Sophie Junker’s soprano was supple and strong as Cupid and Honour.

The company of singers performed Dryden’s many smaller characters with wit and skill, though these smaller parts can be hard to track: Dryden’s unfamiliar story, taking such unexpected and unrelated turns, isn’t always easy to follow – but, often, isn’t important either, as the interim narration (written by historian and writer Hugh McDonald, and delivered with conviction and deft humour by actor and writer Simon Robson) always brings you back to the action. The Vox Luminis instrumentalists, without a conductor, seem able to play in organic unison, just occasionally taking a lead from Simon Linné on guitar and theorbo, building a sound world which is as deeply felt as it is strongly played, while exceptionally sensitive contributions from percussionist Mariana Soroka gave the score added depth and texture.