Just in case anyone forgot, what with his reputation for Stygian gloom and virulent lament, Nick Cave is a taking five from his day job to remind us that he’s a pretty funny guy.

What else to make of a lyric like this one, sung in declamatory frustration, like a man at the end of his tether: “I’ve been listening to ‘The Woman’s Hour’ / I’ve been listening to ‘Garden Question Time’ / But everything I try to grow / I can’t even grow a dandelion.”

The lyric is from “Love Bomb,” from Mr. Cave’s recent self-titled album with his new four-piece band Grinderman — an offshoot of his regular outfit the Bad Seeds. Like everything else on the record, “Love Bomb” is at once tongue-in-cheek and a howl of rage, and it finds the 49-year-old murder balladeer, gothic fabulist, and old-school romantic cutting loose with some of his most outrageous material since his fledgling days fronting Australia’s caustic and bruising the Birthday Party.

“I had no idea what I wanted to sing about,” Mr. Cave said, a few weeks before the beginning of a brief American tour that brings him to Madison Square Garden tonight in the opening slot for the White Stripes. The Grinderman project, inspired by an old blues tune by Memphis Slim, came about as the songwriter itched to do something different after his last album with the Bad Seeds, 2004’s “Abattoir Blues/The Lyre of Orpheus.” As Mr. Cave explained over the phone, he needed to break from his routine, which usually centered around specific themes and a workaday process that involved sitting in an office and knocking lines together until they looked like a song.

“I decided I was going to try not singing about God and not singing about love,” he said. That left lots of room for singing about … sex, or the lack of it, as in the album’s immediate attention-getting track “No Pussy Blues,” which dispenses a twisted tale of priapic woe:” I sent her every time of flower / I played her guitar by the hour/ I pattedher revolting little Chihuahua.”

Working with frequent bandmates Warren Ellis (strings and keyboards), Martyn Casey (bass), and Jim Sclavunos (drums), Mr. Cave made the songwriting more of a jam-based, collaborative affair, even freestyling some of the crazed, preacher-like rants that introduce a few of the tunes.

“I have a kind of a talent for doing that,” he said. “There’s a spontaneity to that sort of thing that can be extremely funny.”

More notably, Mr. Cave, who has nurtured a famous infatuation with American music and its roots, picked up a guitar and learned to play it. The second-hand Fender Stratocaster he found in a Manhattan guitar shop gave him a new kind of agency. He had always played and composed on piano, and wanted to get away from it. “I felt I had to approach music in a different way, and one effective way is to pick up an instrument that I didn’t know how to play,” he said. “And the guitar is an enormously forgiving instrument. Any fool can do it. I plugged it in and it just sounded to me like John Lee Hooker. It’s fantastic fun. You’re just sort of dragged into the music.”

Mr. Cave’s playing, which is raw and jagged, gives Grinderman’s gnarly post-blues a prehensile vigor. Journalists like to point out that the performer will be 50 in September and suggest that the album, with its roaring braggadocio and king-snake snarl, is a bit of a chest thump. And why not? Mr. Cave insists that his fixations are healthy ones. “Am I more obsessed with sex as I get older? That’s a kind of normal thing to hear from every 50-year-old man I talk to. I guess, yeah.”

Meanwhile, Mr. Cave will get to play for his largest indoor American audience ever, sweating up the arena stage with his unhinged lust before the comparatively chaste White Stripes arrive. “Not a bad gig,” he said, “for a new band.”