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 for O’Herlihy. His solution was to design an oval‑shaped PA hung from the ceiling of the venue and directed down towards the audience. “Obviously, in a normal concert situation,” says Edge, “99 percent of the time, the bands are on stage with a PA left and right of the stage, and they’re blasting audio the length of the building. So what we did is we put speakers in the ceiling, so the audio was coming down to the fans.

“Not only did it avoid the issue of massive feedback as we were sort of in the centre of the building, but also it solved the time‑alignment issue that is everywhere. You know, particularly in festivals, where you’re at the back of the stadium and you’re looking at the video screen, you realise that all the lip sync is out, because the sound has taken such a long time to get to you. It’s three milliseconds per metre of throw.”

“That’s probably what I would feel personally was my greatest achievement from a sound design point of view,” O’Herlihy says. “The way the system was configured all the way around in that oval shape, I went left and right stereo image all the way across. So no matter where you were, you got the stereo image perspective of the way the show was mixed. And by doing it like that, you were no more than 75 feet away from the source sound.”

“In this case,” Edge adds, “because the speakers were very close to everybody, there was time alignment across the whole building. Not only did it solve some technical issues, it really improved the quality of the sound for the whole building. And we were really, really delighted with how that worked out.”

“I mean, only with this band could you do it,” O’Herlihy points out, “because there’s a huge element of cost involved.”

“Trying new ideas is definitely part of the spirit of the band and of our team,” Edge states, while saying of O’Herlihy, “He’s never scared to collaborate, he’s always open minded, he’s always interested in learning from other people. So, there’s no ego. It’s just literally he’s got his eyes on the prize of the best possible concert sound.”

Quantum Effects

Pre‑production on U2:UV began eight months before the team could actually gain access to the Sphere. Instead, O’Herlihy and the band worked with a similar surround system at Victorine Studios in Nice. “It’s a big film lot with huge sound stages,” he says. “So the band were in Studio One, I was in Studio Four. In Studio Four, I set up a big grid system, and put speakers up in the grid... just hung them all over the place. I had 32 different destinations, which is the configuration we configured for the Sphere. So I was able to mix on my console.”

At the Sphere, O’Herlihy uses two of DiGiCo’s SD7 Quantum consoles. In France, he also managed to get his hands on a prototype of DiGiCo’s SD8. “So, it was just fantastic,” he says. “I mean, again, they’re leading the field in the advancement, digitally. The new console is coming out, but it was a little too early for the Sphere shows.

“The simplest way to describe how we did the routing and configuration is that each channel has 40 auxiliaries. And with each one of those we put in a destination on the 32 speakers that we had. So you put one channel into destination 6 and 7, or 17 and 18, or 23 and 24, and when you brought the fader up, that would send the feed to that speaker through the auxiliary. That’s the way we figured out how to do it, in our kind of mock‑up version.

“The guys would come over from Studio One, and in Studio Four we had Pro Tools running, so they could listen back to what they had just done, with the imagery and with the movement and all of that kind of surround stuff going on.”

“That was useful,” says Edge, “because we were really trying to understand the immersive aspect more than just the sound itself. We’re going through a similar learning curve with Atmos. There needs to be a focus, there needs to be a discipline. So that’s what was useful in France. We were exploring those parameters and finding where those lines were.”

Pinpoint Accuracy

When O’Herlihy and the band finally got in the Sphere in the middle of 2023, the sound engineer was pleased, and a touch relieved, to discover that the preparation in France had served the team well. “Like with all of these things, you’re hoping for the best when you’ve done all of the homework,” he says. “Everything that we had planned for, everything that we had decided to do, had translated and configured correctly. It was amazing.”

Essential to the process was O’Herlihy’s tailored approach to using the Sphere Immersive Sound setup. “Where the stage is, where the band are positioned, directly above their heads is a thing called the proscenium PA system,” he explains. “How the approach was configured was that directly above Edge, we put his guitar setup. Bono was in the middle, so we set [his vocal] up directly above him. Bram was to his right, and Adam was to his left.

“The best way I can describe it is it’s like pictorial audio. So that when you’re looking at Edge, you’re hearing Edge, when you’re looking at Bono, you’re hearing Bono. If you’re down at the front of the stage, or if you’re on the floor, that directivity is absolutely essential, so that you’re hearing the guitar coming from over here.

“But it’s kind of everywhere,” O’Herlihy adds, “because directly above the proscenium system, we have another 13 speakers with immersive sound. So when Edge is using, let’s say, the shimmer effect, we can put it up there. The immersive thing is fantastic for effects and treatments. I mean, it’s great with Bono’s vocals and the backing vocals, and you can put reverbs and echoes and stuff like that there, so it feels it’s like a decorative thing.

“Then you go further back, to the very back of the building, and you have your surround system. There’s another 12 different speakers back there that give you the surround.”

Full Exposure

The live sound clarity now available to U2 presented certain other challenges for the group. When everyone in an arena can, in theory, hear every note played from the stage, another level of concentration is perhaps required from performers. “Oh, they have to be on their toes,” O’Herlihy laughs. “As Bono says to me, ‘I’m hanging my arse out there to dry. If I fuck up, everybody will know.’ I said, ‘Well, you’ve got to do your homework there, pal.’”

Faced with higher audio production values, U2 brought in their long‑time record producer, Steve Lillywhite, who first worked with the band on their debut album Boy in 1980 and most recently on the ‘Atomic City’ single released in September 2023, as Sound Consultant for the Sphere show. Lillywhite had only ever been involved in live sound once before in the past, and with less than satisfactory results. “Once, in 1979, Ultravox wanted me to mix their live sound,” he laughs, “and it was complete feedback the whole way through. I had no idea. It’s a whole different art form, live mixing, compared to studio mixing.

“But what Edge thought with the Sphere was that it was this new sound system, and it might be good to have someone who was their studio guy to come and try and give a bit more of a studio feel to the sound. Also, because no‑one had ever used this system before, it was a case of, ‘What can we do with it?’ So we tended to fill the sides with Edge’s shimmer, which is a huge part of the sound. And some of the keyboards off the [Achtung Baby] album.”

The Amp Pit

The stage for U2:UV is based on a Brian Eno‑designed turntable and is remarkably bare, with no amps on stage. Instead, all of The Edge’s Marshalls and Vox AC30s, and bassist Adam Clayton’s Ampeg, Matchless and Fender amps, are positioned below the stage. “They’re cocooned in their own acoustic environment,” says O’Herlihy, “which basically means it can be as loud as it can be, or it can be as low as it can be, without being affected by anything. So, we get a really good quality sound from all of those. It is something that we’ve worked on and had to be very diligent about for quite a while to get that right.”

The Sphere show has allowed U2 guitarist The Edge to explore stereo and spatial effects to a much greater extent than in any conventional performance.Photo: Ross Stewart

In addition, in terms of achieving specific guitar sounds, The Edge tends to switch between his traditional amplifiers and Universal Audio’s Ruby ’63 amp pedals. “He has kind of shifted a little bit to Ruby units,” O’Herlihy says. “But he’s always A/B’ing between them and the amplifiers. He’s experimenting all the time with stuff like that. But it’s pretty much the same kit.”

“We had a little bit of a problem with the guitar sounds sometimes being a little bit harsh,” says Lillywhite. “But, y’know, with some work, we got it. And really Achtung Baby has got the most guitar solos of any U2 album. It really shows off Edge’s playing as much as anything.”

“I’ve got some stereo effects,” says the guitarist. “Normally, for me, I’m fairly mono, because in a conventional situation, there’s only a certain percentage of the audience that are in the sweet spot between the two speaker stacks. So [with] a lot of stereo stuff, you’re really catering to 10 percent of the audience. It’s not really that important.

“In this case, there’s an opportunity for me to try some guitar sounds that really are distinctly stereo and immersive. Again, often simplicity is the best thing, and you don’t want to get involved in gimmickry just because you can.”

One major obstacle that had to be tackled during pre‑production was Bram van den Berg’s drum kit being the only loud, acoustic sound source on the stage. “If you were standing on the floor, especially,” Lillywhite says, “if you heard the drums acoustically, you heard them before they came out of the speakers. Everything is processed through the system, and there’s an inherent delay in the whole system. That’s why one of the things that U2 hate the most, which is putting a screen around the drums, we had to do that.”

Drummer Bram van den Berg is standing in for Larry Mullen Jr for the Sphere shows. As his kit was the only loud acoustic source on stage, it was necessary to screen it off to reduce spill.Photo: Ross Stewart

Not everything needed to be reinvented for the Sphere shows. Bono, for example, stuck with his trusty Shure Axient, the digital handheld mic based on the SM58. “It’s a bulletproof microphone for him,” O’Herlihy says. “Because of all the antics he’s been up to, year in year out, tour in tour out, y’know, hopping off everything he could find, trying to break it, we have a half dozen of those dotted around the stage in the event of him having a challenging evening, let’s say.”

First Night Nerves

Despite months of preparation, the team still didn’t know exactly how the show would sound on the opening night. “One of the problems was that the band could never really listen to what it sounded like,” says Lillywhite. “We would run a Pro Tools of them playing. But still, it didn’t feel exactly the same as them playing. I mean, Bono could come out and we would run another vocal so he could hear what it sounded like out front, but you really needed the band playing to get what the actual sound was. So it wasn’t a problem... but it was very nerve‑wracking that first night.”

“First night was a bit of a white‑knuckle ride,” Edge admits. “Because there’s so much prep and yet, until the audience’s in the building, it’s just theoretical. And it was really a thrill, the opening night.”

“Joe was fantastic,” says Lillywhite. “He knocked it out of the park. He’s very calm. He’s very well suited to that job!”

“It was kind of a heart‑stopping moment,” says O’Herlihy, “to come to the end of the show, and look around and just see the incredible, incredible expressions on people’s faces about what they had just seen and heard. For me, it was just sheer relief.”

“Every night he learns something more about what we’re doing on stage,” says Edge. “So, you sort of hear the nuances of the balance. It’s really going from strength to strength, I would say.”

As to where U2 go from here, The Edge acknowledges that the Sphere show will be difficult to top. “Well, I mean, in terms of audiovisual,” he says, “it’d be hard to imagine ever being able to do anything more immersive and elaborate and on this sort of scale. I mean, we could come up with some other kinds of show for the Sphere. We’ll be thinking, I suppose, for the next number of years about touring shows and Sphere shows, because they are different things.

“But it has changed the game, I think, this venue. It really has created a new paradigm within live concerts. I’m fascinated to see what other artists might do with it. I mean, it’s very much a blank canvas. So I’m sure there’s gonna be some wonderful things created for this venue. And who knows? Maybe things created by U2 in the future.”

“From an audio point of view,” says O’Herlihy, “it is something that a lot of other acts should experience, and should experience the beauty of it all, and not being kind of fearful. There’s nothing to be fearful about once you get your head around it. I mean, you have to look at it in a completely different light. But I’m sure there’ll be a lot of people come after us. Because, I mean, it is the future.”

With other venues mooted for Paris, Dubai and London, it looks like the ultra‑tech Sphere show is here to stay. “Well, there is a version of the future that has U2 in nowhere else but the Sphere,” Steve Lillywhite concludes. “U2 can keep playing Achtung Baby at the Sphere all around the world. But, knowing them, they’ll think of something new.”