LIFE-changing experiences aren't that common. Perhaps Marilyn Crispell is greedy because she has had two, both radically altering the nature of the focus of her life: the music she makes.

Crispell, who headlines this year's Jazz: Now festival in Sydney, seemed destined to be a classical pianist from the age of seven. But then, having completed four years at the New England Conservatory after her schooling, the American suddenly stopped playing altogether.

"I just needed a break," she says on the telephone from her home in Woodstock, New York. Instead she became interested in medicine and worked in both conventional and psychiatric hospitals. Six years later her marriage had dissolved and Crispell was living with a friend who had a huge jazz record collection, a genre Crispell was unfamiliar with.

One night in 1975 she was alone in the apartment and happened to play John Coltrane's 1964 masterpiece, A Love Supreme.

"I put it on, and it was like one of those comic strips where all of a sudden there's a bolt of lightning," Crispell recalls.

Instantly she wanted to take up playing again, now as an improvising pianist. Within two years she was performing with the best musicians in the field, playing heady, dense and sometimes complex music. Her future seemed assured.

Then came life-changing experience No.2.

In 1992 she heard the great Swedish bassist Anders Jormin. "He's a very beautiful composer and a very beautiful player," she says. "It touched a chord in me.

"I think I was at a point where I wanted to allow a more lyrical quality in my playing and it happened to coincide with being there and hearing him."

I suggest to Crispell that, along with this sudden switch from density towards lyricism, she has also come to astutely use silence as a tangible component of the music.

"Violence?" the musician responds in surprise.

"No, silence," I repeat and laugh. "I bet I had you worried for a moment, then?"

"No, no, no," she chimes. "I was getting ready to give an interesting answer. But yes, I have become much, much aware of silence, much more aware of playing to the room.

"Last night I played a concert here in Woodstock. It was evening and you could hear the crickets outside. I played a note and it was very resonant and I was very aware of the space around it; of allowing it to have its own space before I went on to the next note. I think when I was younger I was very geared up and just wanted to play as fast as I could and as many notes as I could. I think I was trying to escape gravity."

Now she finds sparseness "exhilarating and liberating. The one thing that I do try to stay away from is anything banal. I guess I deal in extremes a lot."

At Jazz: Now, Crispell will perform solo and with locals Lloyd Swanton (bass) and Simon Barker (drums). The festival opens with the triple treat of the Sam Keevers Quintet (featuring Bernie McGann), pianist Mark Isaacs (solo) and the Andy Fiddes Trio. Crispell plays solo, followed by the Jackson Harrison Trio, on Thursday.

September 12 has the Stu Hunter Experiment, the Andrew Robson/John Pochee Duo and the madcap Alcohotlicks. Informal Troupe play before Crispell's trio performance on September 13.

She enthusiastically commends adventurous jazz to those unfamiliar with it. "It's very emotional. It's like a journey," she says. "[People] don't have to know something about this kind of music to relate to it. It goes through a lot of different spaces."