Acoustic meets acerbic

“This is a rock concert, not a ... tea party, all right?!”

Billie Joe Armstrong of Green Day was looking for some punk- rock spontaneity Sunday, urging more and more fans into the pit at the Universal Amphitheatre for the second night of KROQ’s annual Almost Acoustic Christmas concert.

Green Day closed the show by performing its ambitious new album, “American Idiot,” in its entirety, a bold move for any band with a history of hit singles that fans actually want to hear. That was one of a handful of surprises at the seven-hour concert, which also had two ex-members of the Police joining Incubus for three songs.

The Acoustic Christmas shows are now a tightly run machine, with each act appearing suddenly on a rotating stage for quick half-hour sets. But Sunday was also like two concerts, divided easily between the bands that played before Social Distortion and the more sophisticated acts that came later.

It was during Social D.’s set that the night fully took off, and at that point the concert seemed like a truly good place to be, with a stirring blend of punk energy and personal warmth epitomized by the band’s newest KROQ hit, “Don’t Take Me for Granted.” As the band with the longest association with the station, Social D. dedicated the early signature tune “Mommy’s Little Monster” to DJ Rodney Bingenheimer, who first aired the song on the station in 1983.

Likewise, what makes Green Day a great live band is not just the music but also a genuine affection for its audience. During “City of the Damned,” Armstrong pulled a preteen punk with big, spiky hair onstage. “Wanna stage-dive?” he asked, before preparing the pit with a safe cushion of raised hands. A new hooligan was born.

Green Day has found a kind of perfection within a limited musical formula of melodic punk rock, but has stretched out with “American Idiot,” a thematic collection that mingles the personal and the political. Armstrong dedicated the mournful “Wake Me Up When September Ends” to the late Johnny Ramone.

Incubus found sudden melodic flourishes within its powerful, noisy, funky arrangements, a layered sound more interesting than its pop popularity might suggest. And Incubus was flexible enough to perform the ‘80s Police hits “Message in a Bottle” and “Roxanne” when the band was joined by drummer Stewart Copeland and guitarist Andy Summers.

Velvet Revolver was another flavor entirely, all sludgy volume and rock star flamboyance. And for a couple of songs the band seemed as if it was playing to the wrong audience, with fans taking cellphone snapshots of the spectacle onstage but not doing much dancing. That quickly shifted as Scott Weiland began singing “Fall to Pieces,” an emotional, soaring ballad that allowed the former Guns N’ Roses players beside him to sound most like their old band.

The first half of the night did include such promising younger acts as Chevelle, with its straight-ahead modern hard rock, but others were the more predictable pop-punk acts that now fill too much of KROQ’s airtime.

Good Charlotte showed a flair for simple pop melody, but it was not about to take its genre (or any other) in a surprising new direction. Unlike Green Day, which can somehow still make its familiar ingredients feel fresh, the songs of Good Charlotte were utterly predictable, pleasant and safe. Sum 41 had the slashing, twitchy vibe of grass-roots punk rock, even if its rocked-up anarchy slipped too easily into a convenient pop melody.

During Papa Roach’s set, singer Jacoby Shaddix showed more energy than many of the night’s entire bands, stomping and shaking and jumping. Papa Roach has dropped the rap from its rock, though not without some new influences. During “Broken Home,” Shaddix suddenly began singing the litany of drug references in the Queens of the Stone Age song “Feel Good Hit of the Summer.”

Some holiday messages are universal.