Recording in an English country house, all five members of the group make a loud, cathartic racket - a habit-busting trick the band has practiced since primary school, says bassist Colin Greenwood.
"And I'm happy to say that success hasn't changed us at all," joked Jonny Greenwood, who would rather leave the percussion to Phil Selway's drums and Thom Yorke's rhythm guitar.
Whether through the primal release of a "big percussion fest" or by severing ties with its record label, Radiohead is giving the distinct impression of a band that has exorcised something.
Since self-releasing "In Rainbows" as a pay-what-you-want digital download last fall, Radiohead has moved quickly with the tilt of innovation. They surprised fans with intimate webcasts; they offered one track, "Nude," in stripped down audio pieces for anyone to remix; they held a surprise concert so crowded that police insisted they move along.
On their seventh album, particularly on songs like the falsetto-rich R&B ballad "House of Cards" and the languorous "Nude," the music reflects the same sense of freedom. The prevailing tone of the new material is - gasp! - a melodic warmth.
And this is a drastic change for what many consider the gloomiest band on the planet.
Meet the born-again Radiohead.
In a recent two-part interview with the band - first with the Greenwood brothers and Selway, second with Yorke and guitarist Ed O'Brien - a lightness was unmistakable. Much funnier than you'd expect, the quintet bemusedly contemplate wearing Speedos while shuffling into a Washington, D.C. hotel room.
They had just performed in nearby Virginia, where torrential rain caused flooding and enormous traffic jams around the Nissan Pavilion. In the apocalyptic downpour, Radiohead functioned as a hearth, exuding their newfound glow.
Five shows into the first leg of their North America tour, they played confidently. At one point, Yorke urged the soaked crowd to "cuddle," an unthinkable prospect for a Radiohead concert.
Tuneful beauty has always been part of Radiohead songs (like the "rain down" climax in "Paranoid Android"), but such moments have seldom been allowed to linger. Asked the origins of the new mood, Yorke is as clueless as anyone.
"I don't know where it came from, to be honest," said the 39-year-old singer, laughing heartily. "I think (`In Rainbows') has its moments of fraught tension, like `Bodysnatchers' obviously. But it ends up in a good space. It starts off pretty anxious, but the end of `All I Need,' by that point, everything is like, `Ahhh' - getting it out of your system."
When the band completed 2003's "Hail to the Thief," they essentially got what O'Brien calls the "machinery" of the music industry out of their system. Their six-album deal with EMI Music Group expired and they declined all suitors for a new deal.
The band was at a crossroads and low on energy. They were disappointed by "Hail to the Thief," which they felt was unfinished.
"What was great about `Kid A' was that it heralded a new period and it meant we went off in some cool new places," said O'Brien, 40. "But the downside was that in the whole period up until the end of `Hail to the Thief,' we picked up some nasty habits."
The band, of whom all but O'Brien still live in their hometown of Oxford, had progressed steadily into more experimental territory after their 1993 debut "Pablo Honey" and the classic guitar rock follow-up, 1995's "The Bends." The unparalleled "OK Computer" (1997) elevated them to worldwide fame, but didn't tame them. 2000's "Kid A" and its companion piece "Amnesiac" followed.
The outwardly political "Hail to the Thief," something of a return to guitar-based rockers, was the first sign that Radiohead's path had become confused. Afterward, the band members occupied themselves with their families. Yorke released a solo album, "The Eraser" in 2006.
"We were going along in a certain trajectory and then suddenly with `Hail to the Thief,' it was: we can't carry along in that way anymore," said Yorke. "To me the hardest thing was finding a reason to carry on."
As unified as "In Rainbows" sounds, it took years to complete. The band began recording it with producer Mark Stent, the first time in years they didn't work with Nigel Godrich.
The attempt was futile and Radiohead set out on tour to help bring the new songs into shape. When they returned to the studio, they went back to Godrich, considered the unofficial sixth member because of his importance in helping refine the group's sound. (Colin calls his wealth of gear "like Aladdin's cave.")
"The key thing in actually propelling it forward was Nigel coming back into the process," said Selway, 41. "The reality when we got in there was it still wasn't good enough. We really had to raise our standards quite a lot."
Typically, songs begin with Yorke writing something on piano or guitar with vocals and fleshing it out with the multi-instrumentalist Jonny Greenwood. Then the band works together to find the right arrangement, a process that can be tortuous. "Videotape" underwent, Yorke jokes, hundreds of versions before finding the right minimalist sound.
"We still sometimes get overawed by the songs," said Greenwood. "We'll get very attached to a song as an idea in its very basic form, but we also know we can't really leave it like that. So that's what we spend our time talking about and planning and thinking about. Thom will sit and play `Pyramid Song' on piano, for example, and it's obviously not finished. It needs a rhythm to propel it along. But what do you do with it and yet not mess it up? So that's the sort of enjoyable pressure we like to be under."
Though the method of release overshadowed the music of "In Rainbows" somewhat, it's been almost universally hailed as a masterpiece. Yorke has been quoted as calling it "our classic album, our `Transformer,' our `Revolver,' our `Hunky Dory"' - a statement he said is a misquote: "I do talk some ... but I didn't say that."
His point, he said, is that they strove to make a similarly concise work as those albums.
"In Rainbows" may be a departure, but it's unmistakably Radiohead. Yorke is still singing about disconnection between people, which he cheerfully acknowledges: "It's part of my repertoire. It's what I do. Some people go and work at something they don't like, others talk about disconnection a lot."
But the album still feels apart from the old Radiohead story line. For the first time, they don't sound self-conscious. The band says it all starts with being free of a record contract. (The album was also released traditionally on Jan. 1 by ATO imprint TBD Records, topping the sales charts that week. The band has declined to release sales figures for the download.)
"When we weren't signed to EMI and didn't have a contract, that threw up all this mad(ness)," said Yorke. "In a way, your possibilities are endless and limitless and meaningless. You actually suddenly have - I don't know why, it doesn't make sense - but there was a complete lack of connection with our past."
The band has called the digital giveaway a "one-off" experiment, but they've also re-examined other ways they conduct business. They last year commissioned a report from the company Best Foot Forward to judge the carbon and ecological footprint of their touring.
Any adjustments are in the early stages, but the band has posted messages on their Web site urging fans to car pool to concerts. They caution that music is at the heart of any new endeavors.
"The truth of the matter is that none of those rethinking things would be occurring if we weren't vibed up on the fact that we finished something. The energy always comes from an excitement about what one has done."
And as might be expected for the ever forward-looking Radiohead, new songs are already in the works, though they are still just "on guitars," says Jonny Greenwood. He only hints that the songs explore "absurd musical ideas."
"When you hear Thom and Jonny in the soundcheck and they've come up with something and start playing it, it's good to hear," said O'Brien.
The process of finding the right instruments for the songs will soon begin. Greenwood would like to even throw a banjo into the mix, but said he gets "level looks" from his bandmates whenever he brings it out. "There's a ban on banjos," said his 38-year-old brother.
"What's interesting to me is very old technologies like orchestras and pianos and things and how they meet modern recording and treatment techniques," said Greenwood, 36, who also does classical work on the side, including the buzzing, unforgettable score to "There Will Be Blood."
Radiohead will tour Europe in June and July before returning for the second leg of their North America tour, which will kick off Aug. 1 at the Lollapalooza Festival.
In the meantime, Yorke - who said he still considers the album "the most satisfying format" - has already envisioned the next innovation to deploy when they have new music to release.
"Let's leave it on the street corner with a little sign," Yorke jokes as excitement sweeps over his face. "Now that's a good idea! I like that idea. With a little photo on the Web: `It's here.' A couple of clues. A little doggie bag."