Five musicians are submerged in five tanks, hair slowly undulating, fingers turned pruney. It’s an arresting sight – eyes are round and glassy, movement is restricted and slow. The sounds they make, playing a variety of instruments both recognisable and foreign, put you in mind of any number of marine mammals: mournful, haunting, and decidedly aquatic. One woman, shrouded in a red gown, floats to the surface and then back down like some awe-inspiring selkie, emitting strange, wordless tones with a bubble in her mouth.

AquaSonic, Sydney FestivalLaila Skovmand. Photo © Per Victor.

Created by Danish art group Between Music, this is AquaSonic, billed as the first underwater concert in the world. Uniting five musicians from disparate backgrounds – a classical violinist, a pop-rock vocalist, a jazz drummer, and a singer-songwriter – its mission statement is “a shared passion for the impossible”. The idea for the project originated in 2002, when the group’s Artistic Director and singer Laila Skovmand became curious about what her voice would sound like if it made contact with water. “I got the idea that if I maybe sang into the surface of the water,...