Like a constantly flowing river meandering through an ancient rock canyon, the Slip has been burrowing its music into the welcoming consciousness of today’s indie rock and jam audiences with a passionate, multi-hued, thoroughly intoxicating vibe. Eisenhower, the band’s first studio album in five years and a sublime creative achievement, marks the Slip’s 10-year anniversary. In a recent interview, bassist Marc Friedman and drummer Andrew Barr describes what makes the Slip so indescribable.

GETTING THE RIGHT TONES: The band has hit “a grown-up stride.”

What took so long to get Eisenhower out, and how is it different from what you’ve done in the past?
Marc: It’s kinda the way we’ve been working on things over the last few years. We’re not rushing anything. We’ve been developing these songs for a while and eventually they take on lives of their own. This time out we’re working out more structured songs and then going at it with a normal Slip approach, which means there’s room for experimentation and we can really embrace the sonic color palette that we’ve laid out for ourselves. Instead of wondering where a song is going to go, we focused a little more on getting the right tones.

You’ve been so creative for so long, can you look back over the last decade and figure out what your habits and patterns are?
Andrew: There are certain harmonies we fall into a lot that can be attributed to the Slip sound. I can see there’s familiar emotion that runs through our stuff and there’s a certain sense of rhythmic playfulness that happens. One of the best things you can do is take something that’s your own and turn it upside down, and we’re guilty of that all the time. We’re reinventing ourselves again and again.

That’s what so amazing about the band. You’ve been able to reinvent yourself without losing your audience. Have you seen changes in your audience over the last 10 years?
Marc: It’s a growing audience, definitely, which is a good thing. Right now it’s a healthy mixture of fans who are expecting us to do whatever we want every night, so they have an open mind. But in the last year or so we’ve received the most visibility and those younger fans hear our song “Children of December,” or they know us from the Guitar Hero [video game] soundtrack, or MySpace and they check us out.

Andrew: As artists I think we’re doing a good job combining different sounds and styles with a familiar emotional undercurrent. We really like artists puts on it. I think the Slip could put out a bluegrass album or a reggae album and people would still know it was us.

Marc: That can be said of my favorite acts, too. I have a hard time describing the Flaming Lips, Animal Collective, or Wilco — it’s impossible to describe those bands in two words.

Why can’t you stay in one place? Major rock bands sometimes sing the same songs for 20 years.
Marc: We’re like a frustrated little kid not always content where he’s at, the one with ADD who’s looking out the window all the time. People say, “You’re very creative, you’re special.” But we don’t know; it’s just what we do. And we’re changing humans too. You have new realizations about things in your life all the time that don’t exist in your music, so you have to build them in. When we made this record, for example, we all had just ended long-term relationships so there was a need to voice things differently. We grow depressed if we can’t communicate how we’re feeling now or if we’re looking for a feeling in a song that’s already written and we can’t find it.

Does this mean the band’s growing up?
Marc: I hate to put it that way! But we’re coming into our 30s, and there’s the stuff we all experience with love and business and family. That’s something the Slip has been processing.
Andrew: The more bogged down you get with responsibilities, for me, the more I greet sitting down behind my drums as a real access into joy. It’s a privilege of going into the world of your imagination — the child mind is inspiring. The studio is a place where we get to hold onto that.

You’ve always had a jazz undercurrent in your work. Does that influence still play a role in the slip?
Marc: Sure, but this is a new chapter to the book. In the last couple of chapters we were way more in touch with our jazzier side. We focused on our own abilities and studied the works of Coltrane and Mingus relentlessly. It’s more fun to play indie rock with that ability in your fingers. We have seasoned and molded ears that come from our jazz studies. It might not seem authentic to the rock world, but it’s more fun for us.