On Black Sabbath's new album, "13," the band looks back to its first albums, offering up a dose of the bare-bones gloom and metal thunder that paved the way for an entire genre of music.
The return to the early sound is due in part to the current lineup - "13" is the first full-length studio recording featuring three of the original members: vocalist Ozzy Osbourne, bassist Geezer Butler and guitarist Tony Iommi since 1978. It's also because of bearded producer Rick Rubin, who helped the band get back to its roots.
Iommi, the band's guitarist and only continuous member since the band's beginnings, says over the phone from England that working with Rubin forced him to forget about 40 years of recording experience; the producer had him playing solos live and prevented him from adding additional guitar parts to the songs.
"Because you end up going in the studio, and you say, 'Oh I know, I'll put another guitar on top of that, I'll do another vocal and double track that,' you just get carried away," Iommi says. "He says, 'Treat this album like it's your second album,' and that's how we looked at it, as a followup from the first album."
"13" marks the band's second attempt to work with Rubin, after an abandoned session a few years ago. Iommi says that this time the band, especially infamously unpredictable lead singer Osbourne, was more focused.
"We were really ready for it, we all wanted to do it. That's the difference, wanting to do it," he says. "I've never seen Ozzy as on the case as he was for this album. It was a different Ozzy to what I've known for years, because Ozzy would have a habit of not being there for too long - he'd get bored and disappear - but he was there all the time, all the rehearsals, everything, it was just really how it should be."
Founding drummer Bill Ward sat out the album and current reunion shows because of disputes with the rest of the band - he says it was contractual; the other members say they just weren't sure his health would allow him to keep up with the grueling concerts. Rage Against the Machine drummer Brad Wilk joined the sessions at Rubin's recommendation. Iommi says it took a week or so, but Wilk eventually clicked with the band.
"He reminded me of Bill, he was coming up with ideas while we were recording," Iommi says.
Complicating the recording of "13" was Iommi's fight with lymphoma, which he learned he had in 2011. While most of the recording was done in Los Angeles, at one point the band traveled to England to work in Iommi's home studio while he received treatment.
"The days I didn't feel well, they'd understand," he says. "I tried to not let it get in the way, but it's hard, because you get sick and throw up, it makes you feel very ill, but they all understood and were all very patient and we managed to write quite a bit of stuff."
The launch of "13" and the subsequent onslaught of photo shoots and interviews (which Iommi says limited precious rehearsal time for the tour) is worlds away from what the band experienced in its early years, when the members' embrace of occult-style imagery created a culture of fear.
"There weren't things going on like us, we weren't allowed to do interviews in the early days, we were kept from the press, and then the press got frightened, they didn't know anything about us," Iommi says. "It was quite hairy in some cases, we had some real strange people coming out, witches, or so-called witches, then the church started, we had so many different things going on. It was quite challenging, really."
On their current 20-date U.S. tour - the closest dates to Chattanooga are a Tuesday show in Bristow, Va., and a Wednesday show in Tampa, each about 570 miles away - the band will revisit some of that early material alongside songs from the new album, something Iommi says he still enjoys.
As for plans going forward, Osbourne recently said in an interview that he would like the band to record again, possibly with Ward, though Iommi says that his health makes it difficult to make any long-term plans.
For now, he's focusing on touring in support of his second album.
"It would be a lovely thing to do another album," he says, "but I don't know."