Awkward moments are to be expected if radio station WRZX-FM (103.3) returns to relevance after years of allegiance to one-dimensional bands the likes of Godsmack, Disturbed and Staind.

The station presented its annual X-Fest on Saturday at Verizon Wireless Music Center, where a variety of music provided a refreshing jolt. On the eight-band bill, “modern rock” was defined by the theatrical metalcore of Framing Hanley, the arena jams of Sick Puppies, the progressive artistry of Hurt, the gutter rhymes of Hollywood Undead and the hallowed nostalgia of Alice in Chains.

The awkward part arrived when so few in an audience of 17,000 recognized pure rock ‘n’ roll when played by Kentucky-based band Cage the Elephant.

Vocalist Matt Shultz resembled a protopunk archetype while prowling the stage — detonating the energy of Iggy Pop in 1972 or Jerry Lee Lewis in 1957.

Yet most of the crowd responded only to the song featured in WRZX rotation, “Ain’t No Rest for the Wicked.”

Cage the Elephant, led by spastic headbanger Shultz, aced a lot of other tunes. “Back Against the Wall,” for instance, blasted garage rock as authentic as what’s heard on the Standells’ “Dirty Water” or the Premiers’ “Farmer John.”

If audience members were indifferent to Cage the Elephant, many faces conveyed disbelief during Hollywood Undead’s performance.

Six wild rappers were the last band to appear before headliner Alice in Chains.

Hollywood Undead’s live act is unpolished and built upon crude sex rhymes plus pronouncements of being “so high we’ll ride all night.”

Johnny 3 Tears, Charlie Scene, J-Dog, Deuce, Funny Man and Da Kurlzz employ a strength-in-numbers approach that’s worked well for the rappers of Three 6 Mafia. Eminem is an obvious lyrical hero for the men of Hollywood Undead, and Limp Bizkit may have influenced the sense of general commotion.

But while Limp Bizkit’s Fred Durst placed a laser focus on violent energy, Hollywood Undead offers benign chaos — whether detailing party plans or reporting on society’s demise.

At the end of the night, Alice in Chains unleashed a mighty drone that made the band the heaviest stars of the grunge era.

New vocalist William DuVall supplied enthusiasm and revealed no deficiencies in his role as successor to the late Layne Staley.

This comeback is defined, however, by the monster tone of bass player Mike Inez and the psychedelic riffs of guitarist Jerry Cantrell.