Maybe it was the stringy black mullet. Or the word “RED” tattooed on his neck. Or the fact that a white guy from sweet home Alabama could spit syllables faster than a wood chipper.

Whatever it was, it was difficult to miss Yelawolf over the past two years. Last January, “Trunk Muzik,” the Gadsden rapper’s dizzying breakout mixtape, made him the most captivating new voice in hip-hop, delivering dirt-road narratives with mean-street intensity.

And now here we are, 22 months later, with a disappointing debut album and a sad parable about how major-label rap sausage gets made in 2011.

It starts with the artist’s relentless pursuit of blogger attention. Then comes the record deal. After that, a year or two spent in momentum-sucking purgatory where your debut album’s release date keeps getting bumped, bumped, bumped into the future. And when the disc finally lands, it lands with a cruel splat. It’s soggy with pandering pop hooks that dull the sharp edges that got you signed in the first place.

That appears to be the case with Yelawolf’s latest, “Radioactive.” Listen closely and you can almost hear the record executives not hearing a hit. But can you blame them? When Nicki Minaj released her debut disc around this time last year, she tamped down her gonzo aggression with lovey-dovey raps and singsongy melodies. The album could have been wildly innovative. Instead, it went platinum.

Yelawolf, though, isn’t as comfortable in this pop skin. “Let’s Roll” finds him going half-throttle once Kid Rock emerges from some focus group to groan through the chorus. “Hardest Love Song in the World” has a title that apologizes for itself. And “Radio” courts airplay with dishwater melodies while the rapper criticizes program directors for ignoring his underground faves — Goodie Mob, Group Home, Trick Daddy and Black Star among them.

The 31-year-old (born Michael Wayne Atha) is a sharp student of the Southern rap royalty — OutKast, U.G.K, 8 Ball and MJG — and he wisely snags a few of his heroes for cameos on “Radioactive.” It’s alongside the likes of Mystikal, Killer Mike and Gangsta Boo (formerly of Three 6 Mafia) that Yelawolf races through his most spirited and evocative rhymes.

“In this forest, I’m a lonely tree,” he raps on “Hard White (Up in the Club),” a thundering post-crunk duet with Lil Jon. “My limbs are covered in tattoos, and my roots, they run deep.”

When he’s not digging deep, he’s rhyming fast, cramming a profusion of words into tiny pockets of time. And while he never turns his gift for velocity into a shtick, he does frequently blur the line between character and caricature. All kinds of rural working-class images pop up in this lyric sheet: jugs of moonshine, booklets of food stamps, single-wide trailers, NASCAR races, first-day-of-school clothes from Goodwill, the Constitution, drunk uncles and the waft of Cinnabon. Some of these details feel salient. Others feel like silly grabs for redneck cred.

But not on the album’s title track, where Yelawolf weaves metaphorical boasts out of the natural disasters that have pummeled the American South in recent years: “They threw a mountain at me / I got hit with a pebble.”

It’s too bad that lines like that — lines that take you inside the South, inside his town, inside his skull — are so often deflated by the tepid tracks beneath him. It just doesn’t feel like we’re getting the real thing.

That’s why the refrain of “Everything I Love the Most,” a tune about the rapper’s romantic misadventures, feels more like a coded swipe at the guys who sign his royalty checks.

“They don’t want me to lie,” Yelawolf declares. “But they don’t wanna hear the truth.”

Recommended Track

“Hard White (Up in the Club)”