Sphere Sound - Creating U2:UV

Photo: Rich Furey

U2’s residency at the Sphere in Las Vegas is revolutionising live music.

Since opening at the end of September, the Sphere in Las Vegas has been widely hailed as the next level in live entertainment, thanks in large part to U2’s inaugural residency there. Titled U2:UV and based around the band’s 1991 album Achtung Baby, it’s currently set to run until February 2024.

The stats for the Sphere are staggering. Some 366 feet tall and 516 feet at its widest, it’s the largest spherical structure in the world. Inside, it boasts the largest high‑resolution (16k) LED screen on the planet, curving up, over and around the venue’s capacity audience of 20,000. The exterior of the building, meanwhile, features a 580,000‑square‑foot 2k‑resolution screen, which beams striking imagery — a yellow blob emoji, a moving eyeball, the face of U2’s animated ‘space baby’ — out over the Vegas skyline.

The exterior of the Sphere is also a video wall, here projecting U2’s ‘space baby’ into the Vegas night.Photo: @FlyByChicago

Then there’s the ground‑breaking audio system, designed by German company HOLOPLOT and named Sphere Immersive Sound. Comprising 1534 fixed and 300 mobile units of their X1 Matrix Array speaker modules (both their two‑way Modul 96s and three‑way Modul 80‑S variations, with 167,000 drivers in total), it is largely hidden behind the LED screen, and promises the clearest concert sound on the planet. Featuring HOLOPLOT’s 3D Audio‑Beamforming technology, which can project sound, on both vertical and horizontal axes, into very specific areas, even individual seats, and Wave Field Synthesis algorithms to maintain consistent quality of sound waves over distances, Sphere Immersive Sound represents a complete rethink of how live audio works.

Clarity

Both U2 guitarist The Edge and Joe O’Herlihy, the band’s live sound man of 45 years (see box), reckon the Sphere system is a gamechanger. “We’ve never had this level of clarity,” says the former. “So, we’ve never felt that the detail of what we’re doing could be appreciated to this level. As much as it is a kind of throwdown, it’s also an opportunity to really work very hard to deliver a level of dynamics and subtlety in the arrangements that we would have done in the past, but would have been kind of lost. If you try and play really quiet in a stadium, no one’s going to hear you. The wind will blow it away. Whereas, in this case, you really can explore a different type of contrast between the loud and the soft parts in a song. You can play very quietly, and it will carry. So, it’s an exciting option.”

The Edge: If you try and play really quiet in a stadium, no one’s going to hear you. The wind will blow it away. Whereas, in this case, you really can explore a different type of contrast between the loud and the soft parts in a song.

“This HOLOPLOT system is basically the future,” O’Herlihy says. “Audio has been waiting for a development like this for such a long time. The sonic value for me is fantastic. The band have always been very much audio‑oriented in the sense of: we want to give our audience the best possible perspective from an audio point of view.”

SOS attended the opening night of the Sphere and can attest to its — and U2:UV’s — dazzling wonder. Audio‑wise, the surround features in the production are actually used sparingly, which arguably gives them greater impact. There’s the moment in ‘The Fly’ where The Edge’s guitar solo descends from the roof. At the beginning of ‘Where The Streets Have No Name’, the organ intro creeps from the back of the dome over the audience’s heads and towards the stage in time for the band to kick in. But, overall, U2 and O’Herlihy’s use of the immersive sound system emphasises clarity over novelty. “We don’t want to be involved in sort of gimmickry,” Edge stresses. “Sound is still the most important medium for any concert. But it’s not the technology that’s important: it’s what the sound delivers to the audience in terms of the emotional connection. We don’t want to get lost in the options in the technology. What we’re trying to do is just find a way to enhance the experience and make it as potent and powerful as possible.”

“We didn’t go overboard, as such, in what we could have done,” O’Herlihy adds. “I think we were very delicate in the application, in the sense of... we didn’t want to turn it into a movie. It’s a rock & roll gig, after all.”

One standout feature in the show is when the choral voices in the middle of ‘Beautiful Day’ fan out across the dome. “We have this sort of vocal moment,” says Edge. “We’ve put the voices in different parts of the building, to really feel like the audience are in the middle of the sound, rather than it coming from the stage in their direction.”

“So you have a really kind of atmospheric backing vocal section,” O’Herlihy says. “It’s a joy to be able to do that. We’ve gone from, you know, stumbling through our analogue world, into the digital domain, to catching up with the rest of the world in the context of audio. I mean, I’ve mixed in a particular way for years and years and years. But when I was introduced to this, I had to sort of refocus my head.”

Plotting

Plans for U2 to open the Sphere were hatched back in 2021, but were complicated by the fact that drummer Larry Mullen Jr was due to undergo surgery, making him temporarily unable to perform with the band. And so the staging of U2:UV required the involvement of a stand‑in drummer, Bram van den Berg, from the Dutch band, Krezip.

In August ’21, Joe O’Herlihy first flew to Germany to hear the HOLOPLOT system. “Bono said to me, ‘I want you to go over and check out this new sound system that [Sphere developer] Jim Dolan has been telling me about. And he says, ‘Do your best to blow it up...’

“It was the first time that they put 160 of these boxes together at the Congress Center [in Leipzig], an industrial exhibition hall, which they completely treated acoustically. I had my multitracks from the last tour that we did, the Joshua Tree tour [2017‑19]. I brought an outdoor stadium show, I brought a dome show, so there were different environments.

“It was amazing. I was blown away by the thing, so much so that I stayed for a week! I must have driven the German engineers nuts. I was asking them, like, a million questions. Because this thing was so impressive. It was incredible. I had Bono’s vocal mic, and I plugged that in, and I could walk right up to the speaker, and shout and scream and roar into it as loud as Bono would. No feedback whatsoever. I mean, nuts!”

Joe O’Herlihy with a few of the HOLOPLOT Modul multi‑speaker arrays that generate the Sphere’s uniquely accurate immersive sound.Photo: Ross Stewart

Previous Experience

U2 had already pioneered immersive performance in the round on their Innocence + Experience (2015) and Experience + Innocence (2018) tours. These productions involved a main stage and smaller, circular ‘B’ stage connected by a walkway the length of the arena floor, which featured a 96‑foot‑long double‑sided video screen. During the shows, the band moved from one area to another, even performing from inside the screen.

At first, this presented an enormous challenge...