Perhaps all the high-water marks of late prompted Dan Auerbach to talk so lowly of his earlier work.

"When we were making our first few records, we really didn't know what the [expletive] we were doing," the Black Keys singer/guitarist admitted by phone from New York two weeks ago.

It had been a particularly momentous few days for Auerbach's smoking, snaking, Akron, Ohio-reared blues/punk/psychedelic duo. He and his bandmate since childhood, drummer Patrick Carney, had just come off playing Madison Square Garden with Pearl Jam, "The Late Show With David Letterman" and a $28,000 Big Apple fundraiser for the homeless.

The morning of our interview, they found out that their sixth album, "Brothers," landed at No. 3 in Billboard, their best showing to date. Most reviews of the record also deemed it their best yet. For once, the frontman agreed with the critics.

"We didn't know how to write a song back then," continued Auerbach, 31. "We were just starting to get used to playing our instruments. That was fun, and it's fun to hear it because it is so ramshackle and immediate. But we've grown up. We're not the same people -- although we really did have just as much fun making this record. We liked the challenge of it most of all."

You can hear the challenges rise and tumble away on the new album. Instead of the scorching riffs and bursting beats of past Keys discs -- is there a Keys fan out there who doesn't air-guitar "10 A.M. Automatic" on a weekly basis? -- this one features more slow-grinding, thick, funk grooves, introspective songs and cool bits of soul.

It's tempting to credit the album's fresh sound to the site where they started recording it, Muscle Shoals Studio in Alabama, where the Stones, Aretha Franklin and Willie Nelson made some of their best records. Auerbach debunked that idea, though.

"We had a good time, but Pat and I could've made that record anywhere," he bluntly stated. "There was nothing special about the studio or the equipment used. It was run-of-the-mill normal stuff. We had a super-talented engineer in Mark Neill, but the connection that Pat and I have was the key."

That connection was loosened up and tested during a yearlong hiatus for the band. In that time, Auerbach toured behind his first solo record ("Keep It Hid") and produced some younger bands' records (Hacienda, Cadillac Sky). Carney put together a rhythmic ensemble called Drummer (in which he ironically played bass) and split up with his ex-wife (hints of which permeate "Brothers"). The duo also made the "Blakroc" album with Roc-A-Fella co-founder Damon Dash and rappers Mos Def, Ludacris and RZA (a follow-up is reportedly planned).

Auerbach said these diversions cleared away the new paths on "Brothers."

"In terms of songwriting, I started to open up and have fun on my solo record," he recalled. "And then the 'Blakroc' record had a big effect, because we started all those songs for the most part with bass and drums instead of guitar and drums. We had so much fun doing that, we carried it over to 'Brothers.' I think it reinforced the groove on this record.

"Also, working with other people definitely helped us realize how effortless it is for Pat and I to work together. It really is. We could make a record every week if we wanted to."

Two is no magic number

Something else unique about the new record is its inclusion of bass and keyboard parts. The record goes so far beyond the fabled Black Keys two-man formula, in fact, that the duo has added two musicians to its tour caravan: keyboardist Leon Michels and bassist Nick Movshon, who played together in the soul/funk group the Mighty Imperials.

Auerbach downplayed their role, saying they will only perform on some of the new songs.

"We wanted to keep [the arrangements] similar and not have to strip them down," he explained. "So we found a couple of like-minded slackers who will play a few songs with us every night. They grew up together playing music just like Pat and I, so it's not like we're hiring some hot L.A. session players."

As readily as he demystified Muscle Shoals and earlier Keys albums, though, Auerbach was quick to throw away the idea that he and Carney can only function best as a duo.

"You know, we've had creative control over everything we've done, since we started," he said. "If we want a couple guys along to play some shows with us onstage, I don't think it's weird at all. We're not some kind of two-piece novelty act. We're a band. Green Day is known as a three-piece but tours as a five-piece, and no one asks them about it."

A lot of people are also asking Auerbach about a new music video for their howling track "Next Girl." The clip features grainy, Super 8-style footage of babes in bikinis hanging around a swimming pool with a singing dinosaur puppet. At the bottom of the screen, a scroll reads, "This is not the official video. This is an attempt by their record company to bring attention to the band using a ridiculous puppet. The Black Keys hate this video and don't find it funny at all."

Apparently, the scroll was no gimmick.

"Speaking of creative control, that was the one time it's been tested," Auerbach said with a laugh.

"The record label [Nonesuch] put together the video and sent it to us, and we were like, 'This is awful. It's not funny, not smart, and it cheapens the song.' So I wrote a little thing that said the only way we would think about letting the video go out is if they added that text along the bottom of the screen. Well, they did it. And that's the only thing that saves the video in my eyes."

Chris Riemenschneider • 612-673-4658