by RUPERT BOTTENBERG

Jazz bands swing, they groove, they jump, smoke, wail and wig out. Rarely, however, do they rock. A bold exception to that is the Bad Plus, a piano-bass-drums trio from the American Midwest. It's not so much that, in addition to their own excellent originals, they tackle tunes by Blondie, Nirvana, the Pixies and Black Sabbath. It's that they counterweigh the intellectual fireworks of jazz improvisation with the visceral impact of ar-oh-see-kay - a dynamic magnificently displayed on their latest album Give.

The key may well be that, while drummer David King and bassist Reid Anderson cut their teeth on rock and never really left it behind, pianist Ethan Iverson developed as a musician entirely removed from the pop-rock sphere (in a government bunker 30 storeys underground, or so he claimed in an NPR interview). So when the other two present him with previously unfamiliar rock tunes, which often carry substantial cultural baggage, Iverson's able to assess them with clinical objectivity. Just dig his deconstruction of that hoary chestnut "Smells Like Teen Spirit."

"The musical material was actually quite similar, in some ways, to a '60s jazz modal-type piece," explains Iverson, "like for the Coltrane band. The sections of the song all had the same harmony, but they differentiate in another way, in a verse-chorus-type structure. That was the paradigm shift I had to make - okay, we're not dealing with the harmony moving from section to section, we're talking about a static harmony with sections changing because of other factors. So I stepped back from it and thought, how would someone like Stravinsky harmonize this? Then I realized that the song, in fact almost all of Cobain's music, was based on intervals of fifths - that's what moves up and down the guitar. Okay, I've got these fifths that can spread out in all these different directions, so a lot of the harmonies I play in my interpretation of the song have the intervals of fifths radiating and circling each other in a Stravinskyan fashion.

"So all of that stuff that I'm thinking - it's good for me not to have bashed my head around at 15, checking it out. I'm more like a surgeon with a scalpel, taking a look at it."

For Black Sabbath's "Iron Man," however, Iverson's assessment suggests a more intuitive approach. "I had heard a little bit of that riff over the years, so there was some context, but when I really heard the record for the first time, I was surprised at how it sounded. Seems to be one of those songs that everybody sort of knows a little bit, even me, but then, when was the last time you actually checked out the original? It quickly became apparent that we wanted to play it as ferociously as we could. I actually think that our version is in some ways more ferocious than that original heavy metal classic."

At le Spectrum on Monday, July 5, 9:30pm, $32.50

>> Music Listings