The previously unrecorded Drone Mass was described by its composer, the late Jóhann Jóhannsson, as "a contemporary oratorio". Written for voices, string quartet and electronics, it was commissioned and premiered by the American Contemporary Music Ensemble, aka ACME, who toured and recorded with Jóhannsson for almost ten years. Now they have made the world premiere recording of this richly atmospheric work, in collaboration with Grammy Award-winning vocal ensemble Theatre of Voices, conducted by Paul Hillier, also a multiple Grammy Award-winner. The members of both ACME and Theatre of Voices worked closely with the composer many times, both in the studio and in multiple live performances and tours, before his untimely death.

Drone Mass is an extraordinary, mysterious accomplishment which at times bears comparison with the meditative minimalism of composers such as Arvo Pärt or Henryk Górecki. Beginning with strings and voices, but slowly integrating Jóhannsson's electronic techniques into its landscape, the work represents what the Icelandic composer called "a distillation of a lot of influences and obsessions". As the title suggests, those obsessions include his fascination with the musical device of the drone. This was something Jóhannsson felt as a visceral presence, "a fundamental vibration that anchors music and gives you a foundation". He often used both acoustic and electronic drones – sometimes gently underpinning the music, sometimes drowning out everything else. The new meaning the word has acquired in modern times gave it additional layers of resonance for him. Here, his drones have a motivic-like role, shifting and shimmering with hypnotic effect, conjuring different moods, from unsettling to uplifting, as the work progresses.

The album was recorded during May 2019 at the Garnisonskirken in Copenhagen. It was produced by Francesco Donadello, another friend and regular associate of Jóhannsson's. ACME were joined by internationally renowned Danish vocal group Theatre of Voices and their Artistic Director Paul Hillier. They too have a very close connection with Drone Mass, having performed it twice in the US, and in Krákow, with Jóhannsson and ACME. Most recently, ACME and Theatre of Voices gave a further performance in Athens, just four months after the composer's death. Theatre of Voices also appear on other recordings of Jóhannsson's work, including Orphée, Englabörn & Variations, Arrival and Last and First Men. The composer was known for his organic and inclusive manner of writing and performing, along with his collaborative spirit, which is at the heart of this recording.

This eagerly awaited recording of Drone Mass marks the belated arrival of one of the composer's defining works. It is also a moving and personal tribute from some of those who knew him best.