Diamanda Galas at the Auckland Town Hall

The audience was spellbound by Diamanda Galas' performance.

For some it is torture, and they scuttle out of the great hall. That trend starts at the end of the second song. But for most, tonight is simply an excellent night to be tortured.

Nothing kinky, just a beautiful, passionate, and always savage assault on the senses, courtesy of avant garde diva and experimental musician, Diamanda Galas.

She makes divisive music. Indeed, while some are standing up, hands high above their heads, applauding, others take the chance to get the hell out of this torture chamber that doubles as the Auckland Town Hall. Spoil sports. Banish yourselves to your mundane lives. Ears are made to be tortured every now and then, don't you know?

Tonight Galas performs Guilty Guilty Guilty, a work of originals and covers, including great versions of Johnny Cash and Edith Piaf songs, but the true highlights are Screamin' Jay Hawkins' I Put a Spell On You, and her own Baby's Insane.

The great hall is a stunning setting, with Galas - dressed in a black, shoulderless outfit and licks of blazing black hair - sitting alone on stage at her grand piano, with her backdrop the foreboding pipe-organ that reaches to the roof.

It's the kind of gig where wives are pampering their husbands, saying, "There, there, honey. It'll be okay", as their teenage daughters (no doubt aspiring singers) look on in scared amazement.

But tonight, the hubby sitting in the next row wins, and they walk out too, dragging the reluctant teenager with them. Then there's the man in a suit wiping tears from his eyes, and in front of him is an old chap really starting to feel it, with his head lolling, as Galas wails and sings agonisingly.

"She's [expletive] amazing," yells one of the crowd. "And terribly exotic too," purrs Galas with a smile, during one of her few interactions with the crowd.

The opening is a gospel-cum-country number, offset with a beautiful trilling piano that is punched up at the end with a discordant barrage of keyboard carnage.

Shortly after, during the title track (I guess that's what you'd call it) Galas reveals the full extent of her three-and-a-half-octave vocal range. Going from a deep, bluesy croon to a clear squealing note, Galas is an experience to hear.

Hers is not just an operatic soprano voice, its unique quality is that it's like a wail, or a squeal, that is being dragged down a black board.

When she seethes, rather than sings, like this, the lights disguise her, casting her in darkness and, at this moment, she is not human.

While the music is often a blues swagger, that too moves from extreme beauty, to a lilting din, to delightful piano to stunned silence.

The three encores prove Galas has single handedly put a spell - or should that be a curse? - on all of us. Although I do like a few beats when I'm being tortured.

Who: Diamanda Galas
Where: The Great Hall, Auckland Town Hall
When: Tuesday, October 25