In The Making of Americans, Gertrude Stein explains in no certain terms her love of repetition. "Listening to repeating is often irritating, always repeating is all of living, everything in a being is always repeating, more and more listening to repeating gives to me completed understanding," she writes, and goes on to say that "Loving repeating is one way of being. This is now a description of such feeling."

Stein made repetition into an art, but her repetitions were not exact. They were not, strictly speaking, repetitive but more like reiterations. The magic of her writing is that it suggests the actual process of understanding, a continual reworking and revising of a concept, a constant shift in perspective (like her contemporary Pablo Picasso's portraits) so that a concept, a thought, a face or a flower can be understood from all angles. To use her famous boilerplate, "A rose is a rose is a rose" doesn't mean the same thing as "A rose is a rose." The third bud makes it universal. Prince put it more simply: There's joy in repetition.

The Australia piano trio The Necks work in heavy repetition and reiteration with a formula that is almost mind-numbingly simple. State theme, repeat, change slightly, stop after an hour. That's it, and anyone wanting more won't find it. Different records have different feelings: one might lead toward Miles Davis, another Bernard Herrmann, but the agenda is unchanging. Wash, rinse, repeat. And this is where they work their magic of minor alteration. A phrase augments, an instrument drops out, and the listener, lulled by repetition, feels like something has changed when all they've done is taken something away. Yet somehow the music has been changing all along.

But unlike much music that finds it's aesthetic in repetition, the music of The Necks is extremely human. Inconsistencies come because they are people (Chris Abrahams, Tony Buck and Lloyd Swanton) playing acoustic instruments (piano, drums and bass, respectively). Variations happen as players get bored performing the same maneuver over and over. Differentiation from one recording to the next has more to do with slight changes in instrumentation than in the actual structure of the pieces.

Within that framework, the hour-long Drive By is a remarkable piece of work. Abrams' addition of Hammond organ has augmented their recordings before, and makes a dramatic pitch here. It's swirling and psychedelic, leaning away from the jazzy approach of some of their less varied recordings. Despite the simplicity of their method, it's a dense record rich in nuance, and stands along Silent Night, Aether and Hanging Gardens as one of their best.

Photosynthetic is low-concept even for The Necks. Recorded live in Moscow in 2002, pianist Chris Abrams, bassist Lloyd Swanton and drummer Tony Buck barely flex a muscle through the sparse, spacey set. If some of their work verges on minimalist Krautrock, at other times they are more than a little reminiscent of Miles Davis circa In a Silent Way: quiet, slow and emotive. Like their self-titled first record, Photosynthetic might appeal more to jazz listeners, but is more of a challenge to those resistant to very slowly unfolding sounds.