For a few thousand years, venue design has been a mostly straightforward proposition: the seated audience faced a stage at one end of a usually rectangular space. Classical Greek theaters broadened the seating into a fan-shaped amphitheater. The Romans later one-upped them with stadium-type colosseum design — the antecedent to today’s arenas — which when combined with the Italian penchant for ostentatious aesthetics made for great spectacle. But the Greeks had one trick that sticks with us today: they discovered some basic acoustical realities that made sure that Athenians watching the hit fourth-century B.C.E. comedy Lysistrata got the jokes all the way in the back rows.
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Fast forward to September 2023 when what might become the next inflection point in theatrical architecture made its debut: the Sphere, in Las Vegas. At 366 feet tall and 516 feet wide, it’s billed as the world’s largest spherical structure, with a bowl-shaped interior where an audience of up to 20,000 is enveloped by the largest, highest-resolution wrap-around LED screen on earth, covering Sphere’s entire 160,000-square-foot interior. These visual acrobatics extend to Sphere’s exterior, fitted with 1.2 million hockey puck-sized LEDs that can be programmed to flash dynamic imagery on a massive, never-before-seen scale.
Now Hear This
But in a city fittingly defined by spectacle (and with its own Caesarean palace), it’s the Greeks who might have best appreciated Sphere, thanks to its unique sound system, which consists of a staggering 167,000 individually speaker drivers, configured into approximately 1,600 permanently installed amplified loudspeakers. It’s a scale that almost seems to make the current acoustical buzzword “immersive” seem inadequate. The Edge, guitarist with U2, the band whose residency christened the venue this fall, was sufficiently awed, reportedly calling it, “A once-in-a-generation opportunity,” adding, “We all thought about it and decided we’d be mad not to accept the invitation.”
The sound system, by Berlin-based Holoplot, isn’t simply a matter of brute force, however. The company’s X1 Matrix Array system — listed as one of Time Magazine’s Best Inventions list of 2022 — was originally developed for very specific and challenging auditory environments, such as train stations and airports where garbled-sounding communications have historically been the norm, to offer a high degree of speech intelligibility. It’s predicated on two fundamental scientific propositions: audio beamforming and wave-field synthesis. The former can place (or capture; it applies to both speakers and microphones) sounds at very specific points in space and time. The latter is employed to accurately reproduce the acoustical attributes of one sonic environment, such as how its sound reflections propagate, in a different listening space, by creating a copy of the original sound source’s wavefront and other characteristics. (It’s based on 17th-century Dutch physicist Christiaan Huygens’s principle that the propagation of a wave through a medium can be formulated by adding the contributions of all of the secondary sources positioned along a wave front.) Together, they can take very specifically aimed sounds and put them into realistically recreated virtual environments.
This formulary provide a critical ability for Holoplot’s system in Sphere that can give each seat a full auditory experience, versus what happens in a typical stereo environment in which a listener gets a bit more of the right or the left channel, depending on seat position, or even in a typical 5.1.4 surround environment for the same reason. Essentially, in Sphere, every seat is the “sweet spot.”
“Our patented 3D audio-beamforming technology uses intelligent software algorithms to create unique, highly controlled, and more efficient soundwaves than conventional speakers, ensuring that levels and quality remain consistent from point of origin to destination, even over large distances,” explains Holoplot’s CEO Roman Sick, who adds that traditional loudspeaker technology in large venues can result in audio quality that diminishes as distance from the speakers increases, due to the typically uncontrolled nature of sound wave propagation. “[The X1 Matrix Array system] can also simultaneously send unique audio content to specific locations in the venue, creating the possibility for different sections to hear completely different content, such as languages, music, or sound effects, offering limitless opportunities for truly customized and immersive audio experiences.”
Sick, who took over as CEO in 2016, two years after the company’s founding, and whose background includes the intersections of technology with retail and logistics, says he saw the opportunity for the technology that Holoplot had been developing for live environments after noticing how far sound had evolved in other product avenues, such as smartphones, soundbars, and headphones. By the mid-teens products like Apple’s Beats had become fashion statements as well as extensions of reality on city streets. “I could have a fantastic entertainment experience at home or on my phone, but then I go to a live entertainment show and it just feels like kind of smaller stereo experience,” he recalls. “That’s what needed to change.” In fact, he adds, a combination of the penetration of social media and its ironic tendency towards intensely personalizing experiences, and then how Covid would amplify that, followed by the longing it created to return to shared experiences, suggested that bringing a hyper-real audio experience into a live venue would be the ultimate combination.
Audio Catches Up
Sick also contends that visual experiences, from 4K and 8K video to holographs, have outpaced aural ones in the technology sector. “On the visual side in the last few years, we have reached a level of resolution that is above what our eye can actually capture, so every additional pixel doesn't matter as much anymore because we can't really see the difference,” he says. “We can make these screens as tall as a building, if it needs to be. Sphere is a great example: we're now used to large-scale, high-resolution visuals. But I think in order to be more excited about the experience, the other senses that need to be tackled, and the next easily accessible sense is hearing. They do seem to now be on a similar trajectory, in terms of dimensionality.”
However, we aren’t quite there yet, he cautions. What some describe as three-dimensional sound systems actually lack a third axis that he refers to as proximity: a psychoacoustical effect that can put a sound as close as a whisper in the listener’s ear. That, says Sick, is one of the effects that can distinguish Holoplot from a raft of competitors in the immersive live-sound space, including L-Acoustics’ L-ISA and the Soundscape system from d&b audiotechnik, another German company. It’s a narrow but increasingly competitive sector, all focused on live sound applications, from music concerts to corporate meetings and theatrical presentations. The sense of proximity of the sound in Sphere, says Sick, is what the wavefield synthesis component of Holoplot’s technology brings. “You have a sound object that is right in front of your face,” he says. “You are absolutely convinced it is right there in front of you. That’s the difference.”
Sick says Holoplot’s audio solution for Sphere was developed based on the venue owner’s specifications and expectations. “We already had these core fundamental capabilities but we didn't really have a product in the market for entertainment at the time,” he recalls. “We needed to develop a next-generation product, which was on our roadmap anyway, but Sphere gave us a good reason to accelerate that and push forward with a strong partner who could also help us shape that product.” The X1 went through several iterations and ultimately a proof of concept that included building what Sick describes as “one of the biggest sound systems ever” at the nearly 1.3-million-square-foot Congress Center in Leipzig.
Critical to the design was the need to keep the sound system as invisible as possible. That was accomplished by deploying the very large numbers of transducers largely behind the equally immersive interior LED display. The “invisibility” that ubiquity achieves lets Sick contend that, finally, the audio for the next generation of live events has reached the point where it’s on a par with what the visuals can do.
Can Holoplot’s sound eventually meet the kinds of expectations that holographs are now beginning to bring to visual media? Cautiously optimistic, Sick responds, “It’s exciting to think about it.”
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Sphere will open its doors on September 29 with the first of U2’s 25 performances of “U2:UV Achtung Baby Live At Sphere,” and the Darren Aronofsky-directed Sphere Experience, Postcard from Earth, will debut on October 6.