LAS VEGAS, Nev. — It's the rock 'n' roll equivalent of a disgruntled Doberman after a really bad day at the office, a Hungry Man portion of meat and potatoes metal about the horrors of war, being chased down by bullets and dying in the dirt.

LAS VEGAS, Nev. — It’s the rock ‘n’ roll equivalent of a disgruntled Doberman after a really bad day at the office, a Hungry Man portion of meat and potatoes metal about the horrors of war, being chased down by bullets and dying in the dirt.

And it all began with a pretty wedding song.

Awhile back, former Metallica-Voivod-Flotsam-and-Jetsam bassist Jason Newsted went into a friend’s studio to record some tunes that he had written all on his own, playing every instrument and singing, using the Garageband application on his iPad.

The song he was primarily focused on was a wedding gift to his future wife.

“It was mostly an acoustic song,” Newsted said. “I played a 12-string acoustic guitar, I arranged a cello player and everything and recorded a whole bunch of tracks on that thing to make it this beautiful ballad. It’s like that ‘Fade to Black’ kind of vibe, where it’s real mellow in the front and it gets heavy as crap at the end.”

Speaking of heavy-as-crap stuff, there were a few other songs that Newsted recorded as well, with the help of a couple of musician buddies, tunes that owed more to Newsted’s thrash upbringing than holy matrimony.

They were never meant to be released to the public.

“They were only intended for ourselves,” Newsted said. “Then, one of our friends played it for some dude, and the next thing you know, two weeks later, people are asking to sign the band. It really did happen very fast.”

And now, less than a year later, Newsted is calling from a tour stop in California, a week into his first live dates with the new band that bears his surname.

It’s a career reboot for Newsted, 50, who says that he considered himself retired from the music business after leaving Metallica at 37.

“I chilled a little bit,” he said. “I had to rest, man. I had to get myself back together again. I was that beat down. When I joined Metallica, it was ‘86, and we went solid, just nose to the stone for 15 years. I did a couple thousand shows with those guys. It was really pretty crazy.”

Newsted dabbled in other projects post-Metallica, starting a more straight-up hard rock band, Echobrain, joining Canadian prog metallers Voivod, jamming with Gov’t Mule and plenty of others, but a bad shoulder injury sidelined his musical endeavors for a time. And so Newsted focused on a new artistic outlet, painting, for nearly five years.

But then, in December of 2011, Newsted was invited to take part in Metallica’s 30th anniversary celebration, marked by four shows in the band’s native San Francisco.

“When Lars (Ulrich, Metallica drummer) asked me to come and play with them, at first I wasn’t sure, and then he talked me into it,” Newsted said, noting how the shows made him want to make music again. “It was really, genuinely the reaction from the fans and the feeling that I got, the feeling that we continue to chase, as musicians and artists, it really bit me again. The fans brought me back into it. I was truly overwhelmed. I had no idea they were going to treat me as well as they did.”

Shortly thereafter, Newsted was penning tunes, four of which he released in January on Newsted’s debut EP, “Metal,” which is as visceral, immediate and straightforward as its title suggests, from the Sabbath-worthy swing of “Skyskraper” to the harrowing snarl of “Soldierhead.”

Since then, Newsted has been joined by Staind guitarist Mike Mushok.

The band, which also includes drummer Jesus Mendez Jr. and guitarist Jessie Farnsworth, has a full-length album in the can and is touring through the summer.

The smaller clubs the they’re now headlining are a long way from the arenas and stadiums that Newsted played in Metallica.

And Newsted’s still getting used to being a frontman for the first time.

“It’s challenging, man, to play and to sing, it is really freakin’ hard — for me anyway,” he said. “It’s difficult to keep the concrete in place rhythmically and still sing a melody that has nothing to do with the bass parts you’re playing.”

Newsted sounds like he’s enjoying said challenge though, his voice as bright as a number of his new tunes are dark.

“It’s a rebirth, for the right reasons,” he said. “There was something calling me, somehow. And I had to answer that.”