When I meet Jake and Jamin Orrall they are just as budding rock stars should be—hungover.

The two brothers from Nashville comprise the fuzz-rock duo JEFF the Brotherhood, who’ve been warming up denizens of hip neighborhoods for years and are now getting ready to invade the airspace of the masses with their major label debut “Hypnotic Nights,” out this week on Warner Bros.

It’s been a big year for the Brotherhood. Success in their Nashville home base led to a collaboration with Jack White for a release on his Third Man label and a new record on Warner, co-produced by Dan Auerbach of The Black Keys. They came to New York this week to make their “Letterman” debut.

But if all this sudden success has gone to their heads you’d never know it. “Hypnotic Nights,” which has the laid-back catchiness of Rivers Cuomo doing a Vulcan mind meld with Jeff Spicoli, embodies the sound of dudes who can’t be bothered to try being anything but exactly who they are.

As we sit down to chat they begin—as energetically as they can muster—telling me about the night they had before, celebrating their record’s release after the “Letterman” show. It was a late one that involved lots of sake and karaoke.

So you guys were hitting the karaoke pretty hard last night.
Jake: Yeah…

What’s your power song?
Jamin: Any song by Smash Mouth.

Congrats on “Letterman,” by the way. How was meeting Dave?
Jake: We didn’t meet him. He just comes over after and says thanks—that’s it.

I heard you were going to give him a hat.
Jamin: We were going to give him a Cat in the Hat hat. But we forgot it in Nashville.
Jake: We fucked up forgetting that. We’re two for three.

Who else did you give hats to?
Jake: Matt Pinfield and Jimmy Fallon.

How was Jimmy Fallon?
Jamin: He was awesome. He played music with us, hung out…

You guys are the Brotherhood. Do you have any other siblings?
Jamin: We have a sister. She’s an artist. She goes to Art Institute of Chicago.

So the whole family went into arts. Were you all encouraged to pursue it growing up?
Jake: We were encouraged in our decision to become artists.
Jamin: We were encouraged to do what we wanted. I think our our parents would have been equally psyched if we wanted to become football players.

Does your sister ever feel left out that you guys have this band?
Jamin: No. But she’s annoyed with us right now.
Jake: Why?
Jamin: Because she wants to hang out with us. She just texted me, I told her we were doing press. She said, “Lame.”

You guys have been playing a long time. But suddenly you’re collaborating with highly visible artists. How’d you connect with Jack White?
Jake: Nashville isn’t that big. I have a label, he has a label. My office is right down the street from their office. All my friends work at his label, some of his friends work at mine.
Jamin: He asked us to play a show, in Nashville, and then he ended up wanting to put that out.

That was the live record.
Jamin: Yeah.
Jake: And then he introduced us to Insane Clown Posse.

That’s right—how was that?
Jake: It was awesome—those guys are geniuses.

The new record is a little more subtle—really rich and warm sounding. Have you guys been wanting to evolve your sound for a while? How did that happen?
Jake: That was all Dan, really. [Dan Auerbach of The Black Keys, who co-produced the record.] It was just a matter of having more resources.

Did being on Warner help with that?
Jake: Yes, immensely.

How did that deal with Warner come about?
Jake: It came from us not needing them. They came to us about it. We had our own label [Infinity Cat], we didn’t need to be on Warner Brothers, and that helped a lot in the negotiation. Because we were already fine.

It’s like dating.
Jake: Yes.

I noticed “Heavy Days” isn’t on Spotify, but “We Are The Champions” is. How do you guys feel about Spotify?
Jake: That’s probably because Warner distributed “We Are The Champions.” I guess we should probably put the other one up there.
Jamin: I love it. But I hate the ads. I guess I should just pay for it.
Jake: I’m fine with it, but I don’t know. I’ve never used it.

Your 2010 record was called “Heavy Days.” This one’s called “Hypnotic Nights.” Was the day/night relation intentional?
Jake: It’s just supposed to be a pleasant symmetry.
Jamin: We do tend to have a lot of heavy days and hypnotic nights. Also, that’s the name of a daiquiri drink at this bar in Nashville—hypnotic nights.
Jake: It’s made with hypnotic liqueur.

What’s it taste like?
Jamin: Intense.

Check out the video for “Sixpack,” From “Hypnotic Nights”:

[Photo: Jo McCaughey]