Behind the Scenes at the Sphere
Over recent weeks, there has been lots of news about the amazing ‘The Sphere’ location that MSG has developed in Las Vegas that really sets new benchmarks in technology and immersion for a venue.
Paul Breen of the firm is Senior Director of Playback for the firm and after he appeared on a panel at CEDIA 2023 we contacted him to get more information about the installation and its developments. In a Zoom call, he explained more about the project.
Our main interest was in the ultra-high resolution inside surface of the Sphere which is way beyond even 8K. The interior display has 171 megapixels, while 8K is ‘just’ 33 megapixels – so it has more than five times the resolution. The sheer scale of the installation posed specific technical challenges.
The LEDs are Conventional
The display itself is a ‘conventional’ LED-based system, using tiled modules and was developed by Saco of Canada which, Breen said, had done a great job in matching (‘binning’ in the jargon – Editor) the LEDs to give a very high quality and uniform image quality across the display. The company is continuing to work with the Sphere on long term management of the calibration and repair of the system. The installation has been designed so that ‘everything is redundant’ and if an item fails in the playout and distribution, the viewer should not be aware of an issue. Of course, if a display tile fails, that can’t easily be made redundant, but the modules are small, so the expectation is that any issue would not be visible.
The display has a peak brightness of 500 cd/m2 although that level of brightness is not usually needed except for very small highlight areas as the audience is in a controlled light environment, as it would be in a movie theater. Getting the large audience into the space takes significant time and visitors pass through an atrium on the way, so there is ample time for their eyes to adjust to a low level of ambient light. An area of just 1/24th of the display is shown in white to illuminate the area as they enter. The colour coverage of the display is just over DCI-P3.
Some System Challenges
Because of the scale of the building, there are challenges in data propogation and in ensuring that wherever the viewer is sitting that they get high quality synchronized audio. To that end, there are 83 ‘beams’ of audio with huge numbers of speakers and Breen told us that the theater is fairly ‘dead’ acoustically. Partly this is because a high level of acoustic modelling and treatment on the 18″ walls was used to both block the leakage of audio and ensure the quality.
Regular L/R stereo audio cannot be used and the channels have to be completely separate and pre-mixed. (The audio is so good that Bono of U2 is reported to have said it was ‘too good’ and needed more distortion to be ‘more Rock & Roll’!)
Experiments are Essential
Before building the Sphere, the firm experimented with two main small domes at its facility in Burbank (there have also been others). One is very small – just 1/14 scale and with a 27′ (8.2m) wide display – but you can fit people inside. Resolution is less than 4K and there are just a ‘bunch of seats’. Nevertheless, Breen told us, a test video captured on the Goliath roller coaster from Six Flags, Atlanta, can be ‘vomit-inducing’ because of the degree of immersion. Great care has to be taken with bigger installations to avoid discomfort for viewers.
A second dome that is 1/4 scale was also built ‘secretly’ in Burbank in 2020. It was severely damaged in 2021 in a major ‘wind event’. The ‘Big Dome’ studio in Burbank is used for content development and initial testing and has even more pixels than the main Sphere! The Sphere is used for final testing of content outside public hours, so it is effectively in operation up to 24/7.
An intriguing area of testing and future potential for all the domes is in the development of gaming experiences with live content! The Sphere currently supports content from the Unreal engine, so there are all kinds of non-theatrical uses that are possible – for example in virtual production. The group is working on supporting other engines such as Unity, TouchDesigner and Notch. There is work going on to develop hardware for live Unreal sessions. The installations have a lot of scope for interactivity, but there is much to understand and figure out to make it work, without being overwhelming.
The processing of content behind the display is done by a partner company, 7th Sense, who Breen holds in high regard for their pursuit of excellence and with an uncompromising attitude to quality. To quote him ‘they (7th Sense) had to hit it out of the park’ to develop the system. Breen highlighted in our talk that one of the joys of his job is being able to work with ‘the best of the best’ in all kinds of artistic and technical fields. (We have a follow up article planned with 7th Sense – Editor).
The content comes from the servers in tiled areas and is distributed via fiber-based networking to the LED controllers. The pixel processors are the ‘Juggler’ units from 7th Sense and the media server is that firm’s ‘Actor’ system. The content is played out to the displays in 12 bit uncompressed 4:4:4 quality RAW and is streamed directly from the NAS system, under the control of the server. That’s essential as a movie can take up half a petabyte of storage!
The content inside has to be correctly mapped to the 3D space in the Sphere and it can either be pre-rendered or mapped ‘on the fly’. That’s a complex scheme and for live content the resolution is limited to 11K wide, although the full canvas is 16K wide and is output as 25 channels of DCI 4K (around 221 MP in total). The canvas has to be bigger than the display because of the non-rectangular format.
The rendering of the images onto the LED surfaces correctly is critical to a good result and has to be very precise because the pixels are so accurately positioned – unlike a dome or other kind of installation using projection displays.
All in all, as it is today, the Sphere has amazing capabilities and can providing unique experiences, but this is only the start of the journey. Breen told us that the company has been approached to be involved in many high end and innovative projects, so we’ll be reporting for some time to come, it seems!