Green Day

Warning

(Reprise Records)

Punk is one of the hardest things for a band to be these days. Among big fans there’s an orthodoxy not found anywhere else and the mainstream audience is only sporadically interested.

In the past, Green Day’s pop hooks and smiling-faced alienation made the band members big stars. Its breakthrough album, “Dookie,” sold millions and ended up on many mainstream critics’ top 10 lists. Some punks dismissed the band as sellouts, as if The Clash or the Sex Pistols never sold a record.

The band has been going in a different direction since 1997’s “Nimrod.” The cynic would say that’s because “Insomniac” failed to be as big as “Dookie.” Green Day decided to write songs such as “Good Riddance (Time of Your Life),” a weepy acoustic ballad and a huge hit.

The new album presents a more relaxed Green Day. The band’s lyrical content hasn’t changed, but its music is a different breed that manages to sound different simply by playing the average Green Day riff on acoustic guitar and slowing down the tempo.

The second track, “Blood, Sex and Booze,” exemplifies the band’s more middle of the road approach and contains a little lift from the Buzzcocks’ “Ever Fallen in Love with Someone (You Shouldn’t have Fallen in Love With).”

“Misery” shows the band’s penchant for strange instrumental combinations and slowed-down tempos, which they first used on “Nimrod.” Horns and accordions pulse through this tale of the human condition.

But the band hasn’t found a way of marrying its new love of acoustic guitar and half-speed tempos with the energy of its earlier albums.