If you think America's biggest rock band visiting the home of country music is a fish out of water story, you aren't totally wrong. "I don't know any of these people," Foo Fighters' bassist Nate Mendel says while looking at photos of country legends at Nashville's Grand Ole Opry. But juxtapositions make for interesting storytelling, and episode three of 'Sonic Highways' delivers.

Dave Grohl takes the stage at the legendary Bluebird Cafe, the home of singer-songwriters, well, forever; Nashville is home to songwriters.

It's "a country hit factory," Grohl says. An examination of contemporary country music reveals the factory-like process of churning out hit singles. "Tempo, party song, call every girl's butt a sugar shaker," is how producer Tony Brown describes it.

So what constitutes "country"? Emmylou Harris describes the genre as simple songs centered on stories, and that assertion is reiterated throughout the episode by everyone from Steve Earle to Dan Auerbach.

Grohl introduces us to Zac Brown, the only person he knows in country music. The two met in Los Angeles and Brown convinced Grohl to produce one of his band's albums. Grohl describes Brown as an outsider, working outside of the Nashville rules and doing what he wants. "And he rips on guitar," Grohl adds.

The Foo Fighters set up shop at Southern Ground, Brown's recording studio. The joint was previously a church, and after that Monument Studios, the first independent recording studio on Music Row and home to Roy Orbison. Neil Young loves it. Dan Auerbach loves it. Summary: Everybody loves Southern Ground.

At the heart of each episode of 'Sonic Highways' is a song, and the band (along with producer Butch Vig) are struggling with the arrangement of this week's cut. Literally struck by a beam of light from a window in the old church, Grohl hits on an arrangement that works, and he realizes that much of the city's music is grounded in religion. "It's nice to know that there's music that isn't rooted in misery," Grohl notes.

But will too much country leak into the song? The studio, the city, the history, the barbecue -- Grohl begins to get nervous. His band is wearing cowboy hats and playing leads that "sound like they came from 'The Good, the Bad, and the Ugly.'" He needs the Foos to strike a balance between being influenced by the city and staying true to who the band is.

Grohl concludes that he's drawn to the outsiders: Steve Earle, Willie Nelson, Zac Brown, Tony Joe White -- the people who defy the formulas set by the country music industry. "People who aren't just willing to follow," he says.

The song inspired by the beam of light? 'Congregation.'

Next week: ‘Sonic Highways’ heads to Austin, Texas. Get details on the series here.

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