Many times, when people bring a child into the world, they view the world in a different way. They see their lives with a whole new sense of wonder and purpose. For musicians and filmmakers, these new paternal or maternal sensations can be felt in their art.

For the Mountain Goats' John Darnielle and Peter Hughes – both of whom became fathers within a month of each other – getting soft and mushy wasn't really an option.

"I remember after we talked about us both being pregnant, John said to me, 'Don't worry; I'm not going to do that thing when people become parents and suddenly start writing songs about rainbows and butterflies,'" Hughes recalled. "I've already decided our next album is going to have the darkest songs I've ever written."

It may seem strange to be so intent on avoiding "the dad album." However, since their 1991 cassette debut, "Taboo VI: The Homecoming," the Mountain Goats have gained a strong indie following largely thanks to their often honest and heavy lyrical material, which they'll be bringing to The Pabst Theater Tuesday night.

Throughout its over 20-year existence, the band's content has touched upon topics ranging from domestic abuse, drug addiction, loners and tragically truncated careers. The latest album, "Transcendental Youth," is no different. Its opening track was inspired by Amy Winehouse. A later song, "Harlem Roulette," is the story of Frankie Lymon, the '50s R&B singer who died of a heroin overdose at the age of 25.

"I think that's a part of what attracts people to the material," Hughes noted. "There's a darkness and a realness to it."

At the same time, however, Hughes – who performed with Darnielle for several years before officially joining and recording with the group in 2002 – noted there's more to the band's allure than just tragic tales.

"When you come to a show, it's not a bunch of people moping and wallowing in sad songs," Hughes said. "It's really more of a celebration and a communal experience of what people have gone through in their lives. You can have a cathartic event as one person listening to a song, but when you're in a group of 500 other people having that same experience, it becomes really powerful."

The lack of "moping" extends from the crowd into the music. One might expect the Mountain Goats' music to be slow and docile in order to match the serious content often addressed. Instead, many of the numbers are poppy, especially on their latest album.

"('Transcendental Youth') is a funny album because it's probably our most musically varied and upbeat and hooky," Hughes said. "But it's also our darkest with some pretty intense stuff on there."

A small part of the reason for this combination is conscious in order to take the edge off of some of the sad tales told through the lyrics. According to Hughes, however, their unique blend of stories and sound is focused more on just creating interesting music for the listener.

"Any kind of art where there's tension – when it's not just uniformly this or that – it's always more compelling," Hughes said. "There are things pulling you in different directions with light and shade, and other contrasts."

The latest addition to the Mountain Goats' contrasting musical style is a horn section for several numbers on "Transcendental Youth." The idea came to Darnielle while they were trading pre-production ideas for the new album via email.

He was also influenced by touring with Megafaun, who often feature a large horn section on a number of their songs. As a result, the Mountain Goats called up Matthew E. White to arrange horn segments for the album. White, as well as his nine-piece band, is also performing with the Mountain Goats Tuesday night.

"It really kind of brings a lot of extra colors to the music just within the songs themselves," Hughes noted. "It really brings out a lot of the nuances."

The Mountain Goats' addition of horns is just another step toward a more polished and complicated sound, as well as a step away from the band's lo-fi origins, their original calling card in the '90s. And while there are hardcore fans who would love a return to their roots, Hughes doesn't see that happening soon.

"There were ten years of albums, singles and EPs recorded that way," Hughes said. "By the time I came aboard for 'Tallahassee,' just as a fan I was really wanting to hear something bigger and a move to a bigger stage. And I like what we've accomplished just in the last ten years. John's songwriting has only gotten stronger."

That being said, Hughes isn't counting anything out.

"If you do anything long enough, you get bored of it," Hughes said. "We've always talked about if there's ever a last Mountain Goats record, we should go back and record it with a boom box, but hopefully that won't be for a while."

Just don't expect anything about butterflies and rainbows any time soon.