The festival teams the world’s hottest bands with orchestras and innovative composers.

It’s easy to be skeptical about what happens when you stick an orchestra or a Strad-sporting virtuoso in front of a band of scraggly rock musos – case in point, David Garrett’s Rock Symphony album, dubbed Limelight’s “bad taste release of the year” in 2011.

But there is a growing number of intrepid musicians from both camps who are turning the tide away from the dreaded “crossover” disasters of recent years, to draw out harmonious sound worlds from unexpected collaborations and new modes of performance. Whether it’s the Australian Chamber Orchestra playing a program of Nick Drake and Pagninini in a dank Surry Hills pub, The Kronos Quartet covering Icelandic band Sigur Rós, or Radiohead frontman Jonny Greenwood working with legendary Polish composer Krzysztof Penderecki, it seems that hipsters are creating a new brand of classical music.

Vivid Live curator and Sydney Opera House head of contemporary music Fergus Linehan is on-trend: for this year’s festival he has found a bunch of these intrepid alt-pop stars and broad-minded classical composers and invited them to take over the opera house for...