Conductor François-Xavier Roth describes Debussy’s Pelléas et Mélisande as a “…lyric experiment that resembles a door opening out onto what opera could become”. It’s also, in this new recording – made in Lille in an empty auditorium, in conjunction with a production that never saw a live audience – an intriguing door onto what the opera used to be.

If ever there was a piece ripe for Roth and Les Siecles’ period-treatment it’s Pelléas, with its chiaroscuro score, all hazy half-light and shadow-play. We hear – and see – the difference from the very start. Gut strings and period-appropriate woodwind give us a pellucid vision of Allemonde.

Where modern-instrument accounts and their string-vibrato give us an almost tangible, oppressive darkness, there’s a new clarity here, a lightness to orchestral tone that supports but never engulfs or cocoons the voices. This isn’t tragic-horror, it’s mystery, misperception, miscommunication – more moving for being so avoidable.

Roth’s entirely Francophone cast help bring out this humanity in diction and delivery of equal clarity – true sonic theatre. There isn’t...