Earlier this month, Swedish art-pop experimentalists The Knife uploaded this must-see film of their extraordinarily ecstatic stage show to their official YouTube channel. The 90-minute concert performance — which can be streamed for free or purchased as a DVD — borrows some of the best elements from Jonathan Demme’s Laurie Anderson and Talking Heads performance films, as brother-and-sister duo Karin Dreijer Andersson and Olof Dreijer share the spotlight with nearly a dozen androgynously dressed musicians on a multi-tiered but otherwise minimalist stage set. Together they create a wall of ecstatic sound, their impassioned vocals, explosive drumming and mesmerizing electronics amping up the duo’s sound without sacrificing its haunting musical and lyrical undercurrents. The onstage transformation even works on the eerily beguiling “Pass This On” — the closest thing to a conventional pop song The Knife have ever recorded — as Karen plays its catchy steel-drum hook and trades lead vocals with another singer, while her brother and another male performer take part in a romantic dance sequence. The combined effect is both touching and subtly transgressive in a pop music industry that, in many ways, is still behind the times. The fact that Karin and Olof remain steadfastly ahead of their time, both musically and otherwise, can only help move things forward.