Ira and Charlie Louvin, who performed together as the Louvin Brothers in the '50s and '60s, became one of country music's most heralded duos. From the late Gram Parsons to George Jones and the rock band Cake, countless musicians acknowledge the brothers' "blood harmonies" as one of the best sounds country music will ever produce.

A new documentary, "Charlie Louvin: Still Rattlin' the Devil's Cage," premiered at the Nashville Film Festival Sunday (April 22) to a sold-out room of fans and music industry VIPs. The 46-minute film follows the career of Charlie Louvin from the time of the Louvin Brothers until his death last year. Charlie's last-ever interview is interspersed with numerous vintage video clips, family photos, documents and other materials that convey the brothers' significance in country music history.

While the Louvin Brothers were pure country, in his later years, Charlie toured with the likes of Cake (whose John McCrea is interviewed in the film), Lucinda Williams and Cheap Trick. It wasn't the first time the worlds of country and rock collided for the performer, as Charlie notes in the documentary, "Elvis [Presley] opened for Ira and me, but that only lasted a few weeks and then he was hotter than a homemade skillet!"

Charlie also details just how difficult it was for him to work with his brother when Ira was drinking. Asked if he had any regrets, Charlie notes, "I was never able to handle a drinker ... and my brother was a drinker. When he was drinking he hated the world and you could never please him. It didn't take much to get him upset. He was very unsociable but he was an awesome songwriter."

Ironically, in June 1965, Ira and his wife, Anne, were killed in a head-on collision with a drunk driver as they were returning home from a show in Kansas City, Mo.

Emmylou Harris, George Jones, Marty Stuart and Alison Krauss are among those featured in the film sharing memories of Charlie and discussing the Louvins' influence.

Emmylou admits she almost had a religious conversion when Gram Parsons introduced her to the music of the Louvin Brothers. And Marty Stuart offers the assessment that "the name Louvin is associated with country-music royalty. No one has ever duplicated their sound."

"I remember the first time I heard 'When I Stop Dreaming,' notes George. "I almost wrecked the car. I had to pull over and listen to it."

Indeed, throughout their career, the Louvin Brothers offered up such gems as "Cash on the Barrelhead," "When I Stop Dreaming" and "I Don't Believe You've Met My Baby." After the duo split up, both brothers continued with solo careers but it was Charlie who had the most success with hits including "See the Big Man Cry," "I Don't Love You Anymore" and "The Only Way Out (Is to Walk Over Me)." Redemption was a popular topic in their songs as well, with one of their most iconic albums, "Satan Is Real," celebrating a 50-year reissue in 2009.

John McCrea of Cake said the Louvin Brothers sound had endured, and that while Charlie toured with his band there was never a problem with the audience not knowing him or giving him a tough time while he and his band were onstage.

Rodney Crowell, who participated in a panel discussion after the screening, said that the first time he heard a Louvin Brothers song was through his father, who was singing it. To this day, Rodney says whenever he hears "I Don't Believe You've Met My Baby," it is just as poignant.

"That is my favorite Louvin Brothers song," he admits. "I thought it was a ghost story when I first heard it and then you realize it's just that you're not getting the payoff until the very end of the song."

Rodney also recalled playing with Emmylou when they were opening for Elton John at Dodger Stadium. "We were looking down at all these kids with Elton John glasses on and we were singing 'Satan's Jewel Crown' and 'Cash on the Barrelhead,' and those kids didn't know what we were throwing at them."

Singer-songwriter Jim Lauderdale, also a part of the panel, noted that "See The Big Man Cry" is one of his favorite Charlie Louvin songs. He remembered being at the Grammy Awards with Charlie one year. "We were at this party where Charlie wasn't scheduled to sing until 1 a.m. Los Angeles time, but there he was, with more energy than any of us."

Charlie says in the film that "True stories are almost more interesting to the listener than made up ones."

The story of Charlie and the Louvin Brothers is certainly an interesting one. Charlie's biography, "Satan Is Real: The Ballad of the Louvin Brothers," has also been recently released. Copies of the documentary, with profits benefiting Charlie's family, are available from www.louvinfilm.com.

Listen to the Louvin Brothers' "When I Stop Dreaming"

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