When filmmaker Sam Green told Kronos Quartet co-founder David Harrington about his plans to make a “live documentary” about the band – titled A Thousand Thoughts – the musician was a little confused.

“Will it be a movie or a concert or a lecture?” he asked.

The answer is a little bit of each, and all the better for it. The unorthodox film, featuring a live score from the long-running Californian chamber ensemble, was the first part of a thrilling double-header. The second half of the event saw Malian group Trio Da Kali join Kronos to perform songs from their recent collaborative album Ladilikan. While Kronos Quartet may not exactly be a household name, they crossed over to the mainstream like very few classical groups before them, and Green’s film explored the ways in which they blazed a different trail from their contemporaries.

Drawing from archive footage, press clippings and talking head monologues from the band themselves (in on-screen interviews) A Thousand Thoughts charted the lifespan of the quartet, who were as famous for their atypical fashion sensibility as their music at one point in the 1970s. The live documentary format allowed the foursome to perform spine-tingling numbers throughout their career and from esteemed composers such as Philip Glass, Terry Riley and Clint Mansell.

The introduction of Trio Da Kali only sweetened the deal, with Lassana Diabate's virtuoso balafon (an instrument similar to a xylophone) grooves locking in nicely with Kronos' flexible string work – sometimes lush strokes, sometimes delicate plucks. This underpinned Hawa Kasse Mady's powerful, soulful voice.

A multi-faceted treat.