Ever seen a musician play a hydraulophone, a crystallophone or a rotacorda? Underwater? Well Sydney Festival is offering you the chance to experience these peculiar new instruments when it presents AquaSonic, an underwater concert by Danish group Between Music.

^{Nanna Bech in AquaSonic. Photograph © Charlotta de Miranda}

AquaSonic is one of three performances announced today by Sydney Festival as a taste of what is to come in the 2018 line-up. The other two are The Town Hall Affair from the world-renowned New York-based Wooster Group, and an Irish variety show called RIOT.

AquaSonic features five musicians who submerge themselves in five large aquariums to play custom-made instruments and sing – all entirely underwater. “I keep calling it human whale music,” says Sydney Festival Artistic Director Welsey Enoch of the haunting and yet melodic music that emerges.

The creation of the work, which premiered in May 2016, took 10 years of experimentation with scientists, deep sea divers and master craftspeople, leading to the development of a series of very strange instruments. These include a water organ called a hydraulophone consisting of modified gongs...