Pop music is like speed dating: a band puts the essential facts about itself out there as quickly and directly as possible, knowing it may not get another chance to impress. But the conventions of courtship for indie rock bands are inverted. Here a degree of coyness, complexity, opacity even, is what sets hearts aflutter.

Few groups have been as successful at inspiring this latter form of enamorment as The Arcade Fire, the Montreal-based quintet that arrives in New York City for two shows this week. Since the release of its debut album, “Funeral,” on Merge Records last September, the group has been the subject of consistently gushing reviews by the press and incessant major-label advances. In just under five months, they’ve sold over 70,000 copies of the album – an astonishing number for a debut indie rock band.

The band frustrates any attempt to categorize its sound. The list of influences and kindred spirits that spring to mind – Talking Heads, Fiery Furnaces, Neutral Milk Hotel, Pixies, Possum Dixon, Bjork – are so scattershot and contradictory as to be of little use at all.

For a description of their sound, I can’t seem to improve on the disconnected notes I jotted down while listening to the album: post-punk guitar, minor-key arrangements, wild stylistic swings between – within – songs, diverse instrumentation, uneven fidelity, glammy theatrical vocals, Win Butler’s voice sounds like a theremin, (something illegible about) lightning bolts and death.

Even the song titles are dual and cryptic. Four are called “Neighborhood” with second, parenthetical titles (“Tunnels,” “Laika,” “Power Out,” “7 Kettles”); another is called “Rebellion (Lies).”

The lyrics approach a kind of childhood magical realism, taking an animistic view of nature and a fatalistic view of life. But it’s all veiled and abstruse and it’s possible I’m wildly off base here. You can listen closely to a song (repeatedly) and still have no idea what it’s about.

Time keeps creepin’ through the neighborhood
killing old folks, waking up babies
just like we knew it would.

We’re just a million little gods
turning every good thing to rust
I guess we’ll just have to adjust.

And the power’s out in the heart of man
take it out and put it in your hand
what’s the plan?
what’s the plan?

The songs seem to invite the kind of Internet exegesis that indie rock fans perform so eagerly anyway.

Only by tackling songs one by one do they come into any kind of focus. “Crown of Love” is a drunken piano tune that swells into a waltz. After 100,000 more cigarettes, it could almost be a Tom Waits song. “Wake Up” is the kind of gloomy choral material that the Polyphonic Spree might compose if it ever had a dark mood. But in the last minute-and-a-half, it becomes a Muzak version of some forgotten Hall & Oates tune.

All the variation and mystery is exhilarating, but also a little exhausting, and it’s a fair bet that you won’t like all of what you hear. But for those inclined to view – and enjoy – their favorite bands as puzzles, The Arcade Fire is a source of endless fascination.

***

Sabina Sciubba, the ridiculously worldly front woman of the Brazilian Girls, sings in at least four languages (English, French, Spanish, Portuguese) on the groups self-titled debut album (Verve). Her band performs in as many musical dialects: house, reggae, electronica, bossa nova, and something like ska. It is the height of polyglot pop.

Despite the name, the Brazilian Girls (none are Brazilian and only one is a girl) are actually denizens of the downtown New York music scene that’s grown up around the trendy, world-beat club Nublu. And instead of sounding foreign and exotic – as is no doubt their aim – the Brazilian Girls instead sound dreamy and bland. It’s precisely the kind of noir-ish chill-out music I can only imagine people enjoying with a tropical drink in their hand and a healthy dose of psychotropic drugs in their system.

The album’s 12 tracks pass in a not unpleasant, but completely forgettable, daze. Listening is like watching television commercials in a first-world country where you don’t speak the language: everyone is attractive and looks to be having fun, but you have no idea what they’re selling and you’re certain you’re not the target market.

The Arcade Fire plays tonight at Webster Hall (125 E. 11th Street at Fourth Avenue, 212-353-1600) and February 2nd at Irving Plaza (17 Irving Place at 15th Street, 212-777-6800 ).