You may not know the Norwegian indie-pop duo the Kings of Convenience, but you've probably heard their song "Toxic Girl"--it was used in a TMobile commercial about a year ago. "She'll talk to you with no one else around/But only if you're able to entertain her . . ."

If you heard that song, you pretty much heard their last album, Quiet Is the New Loud. It was a pretty album, but after a while it got hard to tell one track from the other. Not that I minded, particularly; their gently flowing acoustic pop suited my ears just fine. The Kings of Convenience resemble nothing quite so much as a cross between early Simon and Garfunkel and Sudan Village-era Seals and Crofts.

But the 2001 remix album Versus was a revelation, if only because adding even the slightest bit of frosting to Erik Glambek Bøe and Erlend Øye's songs made them feel more complete. The Kings have learned from the experience, so Riot On An Empty Street has instruments other than acoustic guitars and Casiotone drums.

That's not to say that they've moved away from their warm coffeehouse pop. Stylistically, Riot picks up where Quiet left off, sounding like Sam's Club was having a clearance sale on major-7th chords and old Left Banke albums. However, the songs vary tempo and meter a lot more than previously. Heck, "I'd Rather Dance With You" even comes dangerously close to rocking out.

Still, the tracks on Riot are largely quiet, introspective, brainy, angsty pop songs. And the Kings' trademark perfectionism is on full display; it sounds like they spent hours considering the necessity and impact of every note on the album. So what works on this album really works. "Sorry or Please" is a great song about relationship ambiguity; "Cayman Islands" is a lush masterwork; "Homesick" is a great ode to lousy minimum-wage jobs. The Jobim-esque samba of "Live Long" is another highlight.

For me, though, the album's masterwork is the closing track "The Build Up," a loping shuffle co-written with guest vocalist Leslie Feist of Broken Social Scene. Feist's vocals recall Astrud Gilberto at her most soulful and provide this album with its most musically interesting moments.

And that just brought out the ultimate flaw in what really is a very nice album--while Bøe and Øye are good harmonists and songwriters, they can sound awfully stiff at times. You don't really notice it until Feist takes a lead, but then it's pretty evident. The Kings did well by closing with "The Build Up"; had it appeared earlier on the album, the rest of the songs would've sounded flat by comparison. Indeed, after hearing Feist purr her way through "The Build Up" it dawned on me that there wasn't a spontaneous-sounding moment on the album up to that point. Like I said, you can tell the care and thought that went into making this album; however, the swing was the first casualty. Even Bøe's little vocal slides on "Surprise Ice" sound forced.

It's fair to say that, while this album is significantly better than the last, the Kings would do well to quit worrying so much about the notes and pay a little more attention to the music. Riot On An Empty Street is not a bad listen, but it's frustrating to hear songs with so much potential being let down by timid, conservative performances.