The tech behind U2's record-smashing tour

The U2 360 concerts are huge by any measure. But on Sunday, with what may have been the largest live-stream ever, the tour got even bigger.

Daniel Terdiman Former Senior Writer / News
Daniel Terdiman is a senior writer at CNET News covering Twitter, Net culture, and everything in between.
Daniel Terdiman
6 min read
The Edge and Bono perform before 96,000 fans during the U2 360 concert Sunday at the Rose Bowl in Pasadena, Calif. Daniel Terdiman/CNET

PASADENA, Calif.--If you were one of the 96,000 people packed into the Rose Bowl Sunday night for the U2 concert--said to be the largest concert ever held here--you were sharing the experience with at least a few other fans off-site.

There's no way to know yet how many exactly, but it's safe to say millions of people around the world were also watching the concert live on YouTube, a potentially server-crashing Webcast that may have been the biggest live-stream yet.

For months, the band has been on tour with its U2 360 concerts. And to top off the grand claims, it has been called the biggest rock tour in history, at least as measured by the size and cost of its infrastructure--more than $750,000 per show, according to Rolling Stone.

Only days ago, the band announced that it would share the Rose Bowl concert live, with fans across the globe. Just before the band came on stage, a roadie calling himself Rocco got up in front of the crowd of 96,000 and said, "Tonight, you are the ones making history," shouting out that those in attendance would be joined by viewers in "North America, South America, Europe, Africa, Asia, Australia, and Antarctica."

Photos: U2 goes global via YouTube

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For its part, YouTube wasn't sharing much about how it put together the live stream. Before the show started, there was some discussion among reporters on hand at the Rose Bowl about whether YouTube would be up to the task of delivering the show to so many people, live, on so many continents. But if Twitter is any judge, the live-stream went off almost without a hitch. More to the point, a Twitter feed set up on the official YouTube U2 page showcased comments in a wide variety of languages from Webcast viewers.

Back at the Rose Bowl, in an effort to rally the capacity crowd, the concert-goers were told why this show was chosen by YouTube: "Because right here is where the greatest singers of U2 songs are....Tonight, we need to hear your voices, and to hear you sing. Can you do it?"

In response, the crowd roared its agreement, and indeed, throughout U2's approximately two hours on stage, there were several emotional moments when U2 leader Bono stopped singing and let the audience take over the vocals. These were truly beautiful and awe-inspiring moments, as there is very little on Earth like the sound of nearly 100,000 people singing together.

Ironically, no connectivity
These days, you can find out what's happening at just about any event by turning to Twitter. But at the Rose Bowl, this wasn't the case. It turned out that there was nearly no connectivity, and so there seemed to be a dearth of tweets sent from inside the concert. Still, because the show was being watched by millions of people around the world, there is certainly no shortage of posts on Twitter about what was happening.

That's an ironic turn of events, though, and not at all what I expected. I thought there would be a steady stream of tweets emanating from the Rose Bowl, and I had expected to send many of them myself. Instead, this highly tech-centric concert was ground zero for a disconnected audience. We were truly "stuck in the moment," to quote one of U2's hit songs, though I doubt anyone wanted to "get out of it."

A YouTube representative did tell me prior to the show that the service was using 24 cameras to film the concert, as well as 24 additional closed-circuit TV cameras. Further, he said YouTube was offering its stream at three different qualities, so that almost anyone could watch, regardless of the speed of their Internet connection.

The YouTube U2 page with the stream of the concert, albeit a rebroadcast. But millions around the world watched the Rose Bowl concert live on YouTube. YouTube

Having YouTube produce such a major Webcast is fitting, given the size and scope of the U2 360 tour. Among its facts and figures are tidbits like this: the 360-degree stage--which allowed huge numbers of fans to watch from behind--featured a 90-foot-tall steel structure, topped by a center pylon reaching 150 feet in the air; the innovative video screen atop the stage weighs 54 tons, is 4,300 square feet when closed, and is 14,000 square feet when opened; the screen itself is comprised of more than a million pieces, including components to illuminate 500,000 pixels, as well as 320,000 fasteners, 30,000 cables and 150,000 machined pieces.

The incredible expanding screen
The video screen, according to information provided by the band's publicists, is "broken into segments mounted on a multiple pantograph system, which enables the screen to 'open up' or spread apart vertically as an effect during different stages of the concerts."

I didn't think I'd ever seen such a thing before, and it just about made my jaw drop when I noticed it. Already, the screen was a sight to behold, but it didn't seem all that big, especially when I thought back to what I'd seen the band do with video during its U2 3D film.

The U2 360 video screen featured an expansion system that allowed it stretch to a size more than three times what it is when closed. Daniel Terdiman/CNET

Well, it turns out I was right: I hadn't seen anything like this before, and neither had anyone else who hadn't been to one of the U2 360 shows.

"The video screen is the first LED screen to be based on a geometric system that allows it to expand in two directions simultaneously," U2 360 architect Mark Fisher told CNET News in an e-mail interview. "Video screens are normally flat panels that track like closet doors, or slatted panels that roll up like garage doors. The 360 degree screen uses a scissor-like motion to expand in two directions. It starts as a solid elliptical ring approximately 20 feet deep, and transforms into form a cone-shaped mesh 60 feet tall."

Fisher added that this is the first time such technology--what he called "transforming geometry"--has been used to "change the shape of a video screen."

And while Fisher said that, in general, the technology behind U2 360 isn't in and of itself new, the way it's being used during the tour most certainly is.

"The show employs a large number of computers and electric motors to control the motion of the screen, and there are large numbers of computer-controlled moving lights," Fisher said. "The video on the screen is also created using powerful computers that 'map' the picture onto the transforming screen. All of this automation and programming is possible because the computers available in 2009 and more powerful, and cheaper, than they were when we created the Vertigo tour in 2005."

Google Earth
Another piece of technology used for the tour--at least in a way that U2's fans can interact with--is Google Earth. Fisher explained that the stage's designers decided it would be fun for fans to see the huge structure on Google Earth.

"So we hooked up with the folks that run the operation, and they agreed to let us put 3D models of the stage into the 3D models of the stadiums where it plays," Fisher said. "The 360 degree stage is turned around in each stadium in six days (and) the models stay in each city on Google Earth for slightly longer."

U2 used Google Earth to give fans a sense of how the stage in its U2 360 tour was built. Here is the London site. U2

On U2's official Web site, the band explained what is going on with the Google Earth project: "If you're following the tour as it moves around...there's a very cool new feature on Google Earth--a model of the 360 stage, in situ, at the venue, about a week ahead of each show."

The site also explained that the model that fans see could be red, green or blue, with each color corresponding to one of three "steel teams" that "leapfrog each other from city to city to build the stage in each stadium."

Fisher also weighed in on the site with the real reason why the band chose to implement Google Earth: "We thought it would be interesting to put up on Google Earth a piece of portable architecture, which is what this structure is," he wrote. "In a way it's got no practical purpose...except that it's fun!"