The sound of whales calling to each other is remarkable to hear - and you'd think, nigh on impossible to recreate on musical instruments.
But Pulitzer Prize and Grammy award winning composer George Crumb uses amplified flute, cello and piano to take us underwater in his work Voice of the Whale.
It requires several special flute techniques - including singing into the instrument while playing it at the same time.
NZSO flautist Bridget Douglas has stepped up to the challenge for a videoed online concert that's part of the revamped Aotearoa New Zealand Arts Festival programme.
As she tells Lynn Freeman, it's actually a work she knows well.
You can experience Voice of the Whale (with sound production by RNZ Concert) online here or head to the Aotearoa New Zealand Arts Festival website.