RADIATION CITY Babies in the corner.

WITH RADIATION CITY, it's seemingly all about the little things. A flit of percussion here, a backing vocal there, just the right shade of echo on a bit of guitar, a fragment of talkback left in the mix. The Portland quintet's new album, Animals in the Median, is an immense treasure trove of these little details, pieced together carefully and painstakingly into a 40-minute symphony of lush, ecstatic pop.

It's not a surprise how texturally deep the album sounds, coming off Rad City's ear-catching debut, The Hands That Take You, and 2012's exquisite seven-track EP, Cool Nightmare. But what's astonishing is learning how democratic the band's process is, in which all five members—Matt Rafferty, plus the band's two couples, Lizzy Ellison and Cameron Spies, and Patti King and Randy Bemrose—are involved in every step. With Animals, the band was quick to record ideas as soon as inspiration struck, leaving the difficult work of honing down the resultant swarms of sounds for later.

"It's like we build this huge building that's gargantuan, that's way over the top," says Ellison, "and then we shave things off to make it smooth and pretty."

This abundance of raw materials, given a focal point in Ellison's elegantly soulful voice, can make Radiation City's sound tough to pin down. There are blips of future-synth R&B and breezily cool bossa nova, alongside hiphop and Brothers Wilson pop. Subsequently, Animals is exotically, almost gratuitously, gorgeous, as if catered with a vinyl obsessive's obscure but infallible taste. The album was recorded gradually at various homes and apartments, including a boozy stint at a farm in Winlock, Washington.

"That was actually where I think the record in its closest form was born," says Rafferty. "A lot of the stuff was written there, and a lot of the concepts came to fruition at that particular point."

For the first time, the band brought in an outside person to mix the songs, choosing Sonny DiPerri to turn their countless tracks into a finished product. Before choosing DiPerri, the band had a few different mixes done by different parties—including one of their own—and asked some friends to pick the best in a blind taste test.

"It was almost unanimous," says Spies of DiPerri's mix. "To me, the difference between our mix and his was openness. Which seems like kind of a subtle thing, but it's a subconscious response. It feels better, for some reason. When we record stuff, we become attached to every little thing—we want to keep all of it. And that just makes everything muddy. Because [DiPerri] didn't have that attachment, he could be more objective about it. It's valuable to have that kind of opinion." Spies adds, "We were all pretty exhausted by the end of it. The record is better for it, but it was hard at the end of it to be objective."

This week, the band returns from a national tour following Animals' May release on Tender Loving Empire. A just-released remix album by G_Force, titled A Different Animal, is further evidence of the scope and pliability of Rad City's sound, which has only expanded since the band's beginnings.

"My theory is that the first album was sort of playful, sad, but not really coming to terms with true feelings," says Ellison. "And then Cool Nightmare was releasing a lot of that emotion, but sort of unconsciously. And this is the conscious effort of really making the songs each important in some way emotionally. I'm sure they each speak to everybody differently, but I feel like it's our most honest work."

"Just getting to know ourselves better in the context of playing music," says Spies.

"I think there's a little bit of a parallel with the arc of the three albums and just how a relationship naturally works," says Bemrose. "The first album was from the period when Cam and Lizzy were first working together and living together, and it had a lot of that nervous, first-date energy. 'Is this infatuation or is this real?'—that question hanging in the air. And the second one was short and sweet, definitely recognizing that there is something that's heavy and good, but still just feeling it out. And this one, there are no bones about it: It is a relationship. That's not to say that it doesn't still feel new and confusing at times, but there is definitely a repartee that has been established so you can play to each other's strengths, and feel more comfortable sharing other parts of yourself."

Spies adds, "The next album will be the 30-years-of-marriage album."

Ellison quickly suggests a title: "Old Balls."