Exploring the Las Vegas Sphere - Audio and Video

The Sphere is a music and entertainment arena in Paradise, Nevada, United States, east of the Las Vegas Strip. The project was announced by the Madison Square Garden Company (MSG) in 2018 as MSG Sphere. The spherical theater inside is known for its immersive audio and video capabilities.

 

The Sphere was designed by Populous, and in 2018 the project was estimated to cost $1.2 billion. Due to design changes, supply chain crises, and inflation, it ended up costing $2.3 billion, making it the most expensive entertainment venue in Las Vegas history. The Sphere opened on September 29, 2023, and the Irish rock band U2 began hosting 40 residency shows at the Sphere. Director Darren Aronofsky's documentary Postcards from Earth was released on October 6, 2023. The venue is primarily used to host award ceremonies and concerts, as well as other entertainment events. While its design is not suitable for the arena layout of traditional sports events such as basketball and ice hockey, it can host ring sports events such as boxing and mixed martial arts, as well as e-sports championships.

1. Sphere Construction Process

The venue is 112 meters tall and 157 meters wide at its widest point. It is the largest spherical building in the world and covers an area of ​​81,300 square meters.

 

The roof of the dome required 3,000 tons of steel. In March 2021, the roof began to take shape and workers began to install 32 trusses, each weighing 100 tons. In May 2021, the trusses were half installed and the crane had to move to the south side of the site to install the remaining parts.

 

The dome was topped out on June 18, 2021, and work was also underway on the outer dome frame built around the dome. The outer dome frame is made of LED light panels and is 30% taller than the dome and can be seen from miles away. Construction work on the interior of the sphere began in August 2021.

 

Once the roof steel frame was completed, 4,600 cubic meters of concrete were pumped onto the roof. This formed a concrete layer that was 10 inches (250 mm) thick and weighed approximately 10,000 tons. The roof was completed in October 2021. Workers then turned their attention to the 730-ton steel interior frame that supports the LED screens and sound system. Construction of the interior frame continued until 2022.

 

On May 24, 2022, the outer dome was capped for the second time. The interior and exterior LED screens were then installed. The latter was lit for the first time during the Independence Day celebrations on July 4, 2023. The sphere quickly became popular for its image displays.

2. How many seats can a spherical theater accommodate at most

The Sphere has 18,600 seats and can accommodate up to 20,000 people (when the stage is at its smallest). The seats do not wrap around the entire sphere, but instead cover about 2/3 of the interior, with the stage taking up the remainder. Due to the overhang of the second floor, approximately 800 seats below the lower level of the venue cannot view the wraparound video screen.

3. External spherical shell LED display

The sphere's shell was equipped with a 580,000 square foot (54,000 square meter) LED display designed by SACO Technologies. It was the largest display in the world at the time. It consisted of 1.23 million puck LEDs, each containing 48 diodes spaced 8 inches (20 cm) apart. It could be used for advertising.

4. Spherical LED display screen inside the theater

The theater is equipped with a 160,000 square foot (15,000 square meters, larger than three football fields) LED screen that wraps around the entire interior wall and ceiling. The screen was designed and manufactured by SACO. According to Sphere Entertainment, it has a resolution of 16,000×16,000, which is the highest resolution LED screen in the world at the time, and has a resolution 82 times that of today's best HDTVs. The screen is composed of 64,000 LED panels, each controlled by a printed circuit board within an aluminum frame, and the panels have 780 different geometric shapes. Due to its curved shape and the tendency of pixels to disappear near the poles, the screen uses adaptive pixel spacing. It is also designed to be acoustically transparent, allowing sound from speakers mounted behind the screen to pass through.

It should be clarified that although its resolution is the largest in the world, its pixel density is not high due to its large distribution area, that is, its clarity is not high. Its average pixel spacing is only 9.5mm, which is equivalent to the domestic P9.5 transparent screen. From the figure below, it can be seen that the LED screen has a large air permeability (about >50%), which is more beneficial to the sound transmission of the speakers arranged at the back of the LED screen.

5. Theater sound system

The sound system of the spherical theater was completed by Holoplot of Germany, using a total of 167,000 speakers. Holoplot uses 3D beamforming and wave field synthesis technology to provide sound control similar to controlling light, bringing a consistent and clear concert-level audio experience, so that every audience member can enjoy a truly excellent and personalized listening experience. The entire sound system can be divided into three parts, covering the entire venue's sound reinforcement system, surround speaker system, and immersive speaker system.

X1 array consists of MD96 and MD80-S, which can be expanded seamlessly

 

1. Sound reinforcement system covering the entire venue

The sound reinforcement system covers the entire venue, including the main speaker array, extended proscenium array and fill array. The main speaker array is equipped with the world's largest speaker array, an ultra-large X1 speaker array consisting of 272×MD96 and 192×MD80-S (33.6 meters wide, 6.6 meters high, covering an area of ​​more than 200 square meters), responsible for the audio coverage of the main audience area, about 25-30 feet (7.6~9.1 meters) from the stage height. 6x effect (FX) arrays (each array contains 24x MD96) are configured on both sides of the X1 speaker array to expand the audio imaging of the proscenium array. In addition, 28x fill arrays are set up, including 10x side area fill arrays, 6x low area fill arrays and 12x fill delay arrays under the balcony area.

 

HOLOPLOT technology can precisely control the propagation of sound waves in the vertical and horizontal axes, so that its energy is limited to a designated area. This prevents unwanted energy from spilling over the boundary, significantly improving speech intelligibility and audio quality. The X1's optimized coverage beam not only directs sound where it's needed, but also avoids unnecessary surface reflections. Its air absorption compensation feature is designed for long-distance applications, ensuring consistent audio reaches the last row of seats up to 110 meters away, with no delay between links.

The entire X1 system is hidden behind a large curved LED screen installed inside the sphere. Although the screen is sound-transparent, it still hinders the transmission of audio, resulting in loss of sound quality. HOLOPLOT has developed a proprietary compensation algorithm to ensure the unique sound quality clarity of X1 by compensating for the angle and frequency losses caused by the LED screen. This effect is similar to a spatial equalizer with a set directivity.

2. Surround speaker system

The surround speaker system is a 71x surround array located behind each audience area to provide surround sound effects.

3. Immersive speaker system

The immersive speaker system consists of 28x ambient arrays (each array consists of 15x MD96 and 5x MD80-S) combined with surround and fill arrays to create a fully immersive sound design. This mode sets the coverage pattern of each array to cover only 10,000 immersive effect seats. This mode was used in the movie "Postcards from Earth". The advantage of the mode is that the sound quality is more delicate. Acoustic reflections are minimized and the sense of hearing seems to come from the near-field speakers.

The 10,000 seats also feature haptic seats that vibrate based on whatever is happening on screen, like an earthquake, as well as 4D effects that can create wind, temperature, and even smell effects. Lucas Watson, President of MSG Sphere, said, “There will be 10,000 haptic seats here that will make you feel the experience in your bones. Whether it’s a rocket ship launching or a boxer’s gloves hitting, you’ll feel like you’re in a spaceship or a boxing ring. We’ll have the wind blowing in your hair, smells, and temperatures like a humid canyon. Creators will be able to take audiences on a journey so realistic that fans will begin to question their reality.”

Other advantages of the sound system

Without wearing translation headphones, you can listen to the performance in your native language in the designated seating area. When the Spanish-speaking public sits in a specific location, they will hear the movie in Spanish, while the audience on the other side will hear it in English. Limit the sound to specific areas of the building to create a unique experience.