A new lead singer is just about the most dramatic change a band can make — even if a main songwriter or instrumentalist leaves, the voice is usually the clearest link to what came before. Although George Clarke, cofounder and lead vocalist of long-running San Francisco avant-metal act Deafheaven, hasn’t gone anywhere, he’s changed up his style so dramatically for the band’s fifth studio album that it actually sounds like they have a different singer. While “Infinite Granite” is unmistakably Deafheaven and continues their progression as one of the most innovative and powerful rock acts of the past 20 years, it’s a big change.

On the group’s previous albums, Clarke sang in a primal, otherworldly shriek common for death metal but rare for a band this musically diverse. That distinction became even more prominent over the group’s last few albums, as the instrumentalists gradually dialed back the serrated, thundering guitars and blast-beats of their younger years and explored more nuanced ways of building tension and intensity, using density, suspense and layers of effects and echo; the guitars now sound less like guitars and more like the ocean or sound effects from Stanley Kubrick’s “2001.”

But where many hard rock bands bring in quiet passages or acoustic instruments for novelty, shock value or a musical daytrip before cranking everything back up to 11, it’s always been part of Deafheaven’s DNA. Even early on, they had more in common with “post-rock” acts like Mogwai and Explosions in the Sky than Metallica, and over the years they’ve become more of an alt-rock act instrumentally (we can remember hearing one of the group’s guitarists warming up before a gig by playing a Smiths riff). But what kept the quintet firmly in the hard rock camp was Clarke’s singing, and the polarity between the violence of his vocals and the group’s increasingly subtle instrumental work was a large part of what makes them so unique.

On “Infinite Granite,” though, he sings almost entirely in a plaintive, gentle style more typical of an alt-rock band — and the change is thrown into even starker relief by the fact that the instrumentalists have continued at their usual pace, making a gradual curve while he’s made a sharp turn. His trademark shriek is heard far off in the distance on a couple of songs, but only returns to its full ferocity toward the end of the album’s closing track, “Mombasa.”

The move isn’t completely unexpected: Clarke had used his calmer register on a couple of songs from the group’s previous album, 2018’s “Ordinary Corrupt Human Love,” and the band has always been creatively restless. But even more than when Slayer slowed down or (in the most fitting parallel here) when Rush’s Geddy Lee shifted to a lower register, the band’s musical dynamic has changed. That jarring contrast — between scary and pretty, between violence and beauty — is a large part of what made Deafheaven unique, and the new sound does take some getting used to. Instead of being a wild fusion of this and that, now it’s more one thing.

Still, whenever an artist changes direction, fans usually say they basically wanted more of what came before, and there’s plenty of that on the previous four albums. A year into their second decade, Deafheaven have launched an entirely new chapter — they can go absolutely anywhere from here.