JOHN BROWN’S BODY IS AN EVER-CHANGING REGGAE BAND!

Tommy Benedetti can name check the reggae greats. “Lee Perry, The Gladiators,” he says. “That was the jump-off point.”

That’s a pretty good leap for a heavy-metal kid who grew up listening to Slayer, Testament and Iron Maiden. But that can happen when you go over to a friend’s house and he’s listening to reggae records. It’s how non-Jamaicans learn about Perry and The Gladiators.

But does that mean you have the right to play it?

It depends on what you do with it. How you put your name on it. How you make it your own.

John Brown’s Body plays Saturday at Water Street Music Hall, and Benedetti has the best seat in the house for the show: right behind the drum kit. He’s been there since the band was born in 1995.

Keeping up with John Brown’s Body is like peering into a kaleidoscope. Everything changes quickly. The band has more former members than current members. Even Kevin Kinsella, who initially put together John Brown’s Body and wrote the music early on, is gone. He wasn’t even out the door before Elliot Martin, who’d joined the band as a backing vocalist, began moving to the front of the stage, taking over the songwriting as well. The nine-piece group — they count their sound tech — can’t even say with certainty anymore where it’s from. “It seems to change month,” Benedetti says. “Right now, it’s three in Boston, three in Brooklyn, three in Ithaca.”

With Kinsella, John Brown’s Body was a tradition-bound reggae band. It really hasn’t been one for a few years now. Sometimes uncontrollable forces go to work. When bassist Scott Palmer died of cancer in 2006, the band could have died as well. That’s when Kinsella and a few others drifted away. But Benedetti and Martin decided to keep John Brown’s Body alive.

With a few changes. “That’s the job of a musician, grow and change,” Benedetti says. “It’s like your life. You take in everything, spit it back out. It’s a natural evolution.

“We were putting together the Spirits All Around Us record” — that was in 2002 — “and the first tune Elliot had written was ‘33 RPM.’ And when I first heard the mix on that song, which we still play, with Elliot’s spitfire vocals, I was completely blown away. I thought, ‘Wow, the band can sound like this?’ It was a completely different vibe.”