Radiohead salvaged a headlining set at the Coachella festival from disaster Friday, following a glitch-plagued opening in which the audio system repeatedly crashed.
The experimental rock icons, booked for the third time to lead the premier festival in the California desert, played most of two songs in awkward, inadvertent silence with frontman Thom Yorke oblivious that the audience could no longer hear.
After twice retreating from stage to deal with audio problems, Radiohead soldiered on with raw renditions of its best-known songs -- including "Creep," the English rockers' 1992 debut single that they have since played sparingly.
Such glaring technical problems are exceedingly rare for a band the calibre of Radiohead -- long a critical favourite -- or Coachella, one of the world's most lucrative cultural events renowned for its punctilious organisation.
But it is the latest in a series of once unthinkable glitches in top-tier events, including an embarrassing snafu in awarding the top Oscar and sound issues at the Grammys.
Radiohead opened powerfully underneath a sea of transcendent light-beams and stars -- a "moon shaped pool," in the words of the title of the band's last album.
Three songs in, the group cranked up the energy on "Ful Stop" with a purple-drenched, crater-laden display that had the feel of a lunar landing, but audio issues were soon sorely noticeable with jarring bleeps over the music.
The sound turned off completely two songs later on "15 Step," with lead guitarist Jonny Greenwood appearing to notice problems. But Yorke, locked in his personal zone with his eyes closed and a sound monitor in his ear, jammed away with passion unaware that the crowd could see but not hear.
- Awkwardness for Radiohead -
Similar issues quickly arose again on "Let Down" off Radiohead's seminal 1997 album "OK Computer," with members of the crowd, after a collective groan, singing along to substitute for the inaudible Yorke.
Rarely chatty on stage, Yorke took responsibility for the technical problems and voiced appreciation to the crowd for staying put.
"I'd like to tell you a joke to lighten the mood or something like that, but this is Radiohead, so fuck it," said Yorke -- making, in effect, a joke about the band's grim reputation.
Radiohead stripped back the sound on several subsequent tunes but did not give up the loop effects that have become a band hallmark. And the sound fortunately pulled through for Greenwood's thundering jolts of guitar on "Creep."
The problems came despite growing technological confidence at this year's Coachella, where drones captured crowd footage, cellular reception stayed mostly consistent and a planetarium-style dome led by Hewlett Packard offered festival-goers a 360-degree journey through space.
One artist who zeroed in on technology Friday was leading DJ Richie Hawtin, who debuted a new live show of free-flowing graphic projections set to the artist's unusually improvisatory brand of techno.
- Introduction to grime -
Stormzy, part of London's fast-emerging genre of grime, voiced delight as his energetic set packed a steadily growing crowd in the afternoon sun.
"This is grime. It's like hip-hop but a lot faster," he explained in a succinct introduction of the genre, quipping that the audience probably didn't think a British artist could rap.
"I don't care if you don't understand my accent," he said, describing his reception as a "glorious occasion."
Skepta, arguably the biggest figure in grime and the latest winner of Britain's prestigious Mercury Prize, was also due to play Coachella but cancelled citing visa problems.
French rap duo PNL also said Saturday it was forced to cancel its Sunday show at the festival because of visa issues.
"After months of administrative procedure, one of us still doesn't have the authorisation to enter the United States for reasons you can imagine," PNL wrote on Facebook.
The duo, made up of brothers Ademo and N.O.S., are also scheduled to play Coachella during its second weekend on April 23.
PNL said one brother is already in California where he "is trying to move things along in hopes of having good news by this time next weekend".
Indie rocker Father John Misty performed on Coachella's largest stage with a chamber orchestra to accentuate his introspective lyricism -- a contrast to his ironic, much-noticed set two years ago that featured a semi-nude, extraterrestrial-masked female key-tar player serenading a woman plucked from the audience.
Up to 250,000 people are expected to come to Coachella over two consecutive three-day weekends, which have identical lineups, after the city council in Indio, California approved a 25 percent rise in attendance.
Lady Gaga is set to headline the festival on Saturday in a preview of her upcoming world tour, while Kendrick Lamar is the final night's headliner in the wake of the acclaimed rapper's latest album release.