As Sotheby’s and Christie’s prepare for the start this week of the major New York auctions of Impressionist, modern and contemporary art — at which a 1932 Picasso is expected to bring in more than $120 million — teams of tech experts, producers and show directors are readying their salesrooms as if they were CNN Central.

They have made more space for roving video cameras, LED screens and expert lighting by shrinking their once-valued seating for collectors and dealers by some 30 percent. Just like a television station, both auction houses have added control rooms filled with producers and directors who watch every camera angle and monitor where the action is in the salesroom. Their attention is not only on auctioneers but on the banks of telephone bid-takers who drive the nightly drama, advising their clients from London to Hong Kong to Doha when competing bids are received. These livestream feeds can “capture the energy of the moment,” Gillian Gorman Round, Christie’s chief marketing officer, promised.

But the massive preparation is not for the benefit of the art world and its V.I.P. clients: Auction houses are now playing to millions of viewers from all over the world, who stream the action live on social media sites including YouTube, TikTok, Facebook and Instagram Live, as well as their own websites — riveted by how the one percent spends its money.

What began as a way of doing business during the pandemic has become the new voyeuristic evening entertainment during the big May and November sales. “Twenty years ago, people thought you had to be the member of an elite club to walk through an auction house door,’’ recalled Adrien Meyer, Christie’s global head of private sales and one of the company’s chief auctioneers. “Now you can see a sale sitting on your couch in your underpants.’’

While many buyers still attend the sales — some observing from the comfort of skyboxes above the auction floor — online viewing appeals to people who simply don’t want to sit in a salesroom for three hours, the length of a typical major auction.

Both companies admitted that fewer big collectors are coming to the sales, preferring to watch the highlights online at home. “This is the age of discretion,’’ said Sandy Heller, a veteran art adviser who has helped put together some of the world’s major collections. “And what’s more discreet than watching a sale at home on your iPad?’’

Even a seasoned auction-goer like Steven A. Cohen, the hedge fund billionaire and owner of the Mets, said, “It sure makes life easier to be able to watch these sales online.’’

Auction houses ramped up their livestream sales during the pandemic shutdown in 2020, “when people couldn’t see art or go to an auction,’’ said Charles Stewart, the chief executive of Sotheby’s. “It was a massive and long overdue moment for us to expand digitally and rethink the physical experience.’’

The first Christie’s auction livestreamed during the pandemic drew about 100,000 people, according to the auction house. Marc Porter, chairman of Christie’s Americas, recalled that the sale, in July 2020, featuring Impressionist, modern, postwar and contemporary art, was a simple production, shot with just one camera. But it helped “launch what is effectively now a Broadway show,’’ he said.

The big three auction houses have since hired production companies and added more channels, transforming these events into what Stewart of Sotheby’s calls “must-see TV,” borrowing the famous advertising slogan from NBC. (While Phillips, the smaller, boutique auction house, has not shrunk its salesrooms, it, too, has made its big auctions available on YouTube, Facebook, Twitter, Instagram, LinkedIn, and, in China, WeChat, Weibo and Red.)

The worldwide reception has surprised experts everywhere. From May 2022 to May 2023, views of Christie’s auctions rose 25 percent, from 3.7 million to 4.6 million, with 10 cameras now capturing the events. (These numbers do not include people watching auctions afterward on YouTube.) “We never expected these numbers,’’ said Bonnie Brennan, president of Christie’s Americas. “It’s the power of social media.’’

While the majority of those watching online are unlikely to have millions to spend on art — and buyers must register with the auction houses to bid — many end up perusing Sotheby’s and Christie’s websites, where they may discover something to buy at other price points, including watches, handbags and jewelry. “We see luxury items as a gateway to art,’’ Brennan added. “It’s about the democratization of access.’’

She added that while the actual number of buyers has remained steady, “the way they are buying has changed dramatically, with 80 percent of bids coming from online channels around the world.” Sotheby’s reported that 91 percent of its bids in 2022 were executed online.

Both say these buyers tend to be younger than the average collector. “They have the confidence that these digital tools are effective, and they feel more in control,’’ Brennan explained. Another major change: the number of collectors who are bidding on and often buying art and objects without having seen them.

Three years ago, Sotheby’s tested a sale with socially distanced bidders in three cities. An Asian collector bid more than $70 million — sight unseen — for a triptych by the painter Francis Bacon. (It ended up selling to an undisclosed telephone bidder for $84.6 million, with fees. According to Sotheby’s, the winning buyer had seen the painting.)

Both auction houses said sophisticated technology has given buyers confidence to acquire works without viewing them in person. Computer software similar to that used by real estate firms or furniture stores can virtually show potential bidders what a living room would look like with a particular work of art hanging over the fireplace or in the entrance hall. Christie’s has a hologram that replicates an object in three-dimensions. When it was selling a Degas “Little Dancer” sculpture from the estate of the philanthropist Anne Bass, the work was too delicate to travel, so experts showed it virtually. It sold for $41.6 million.

“Given that these sales are so highly produced,” said Heller, the art adviser, clients “can have a much better experience simply streaming’’ rather than being in the room where it happens.

With such large audiences, and so much at stake, Sotheby’s auctioneers do far less ad-libbing. An editorial team now writes the scripts for the major sales with a succinct description of each artwork projected on a teleprompter.

“Talking with a teleprompter makes it smoother, more professional,’’ explained Oliver Barker, chairman of Sotheby’s Europe and one of its star auctioneers, who now fields bids not just from the salesroom and telephone bidders but also from online, making the process far more challenging than it once was. (Christie’s auctioneers have the same complications but only use a teleprompter for salesroom announcements, not for actual auctions.)

Professional hair and makeup experts are on hand for auctioneers and the now-visible banks of telephone bid-takers. “I tell the experts there’s to be no scowling; no bad behavior,’’ Gorman Round, of Christie’s, said.

Just like a television show, Sotheby’s even has advertisers. The phrase “in partnership with Samsung” can be seen in the Sotheby’s auction room; on its website and on promotional videos. (The consumer electronics giant pays an undisclosed flat fee). Christie’s said it doesn’t have the same kind of advertising, but during the pandemic its male auctioneers wore Brioni suits and the women were dressed in Alexander McQueen. Both fashion houses are owned by Kering, which is part of Groupe Artemis, the holding company that also owns Christie’s.

Just as Super Bowl parties fire up sports viewers, auction parties are becoming popular, too. Fans online like to talk too.

On the night of Sept. 6, Sotheby’s London salesroom had some 300 collectors and fans watching Barker wield his gavel for the first auction of art, objects, ephemera, and costumes of the late British singer and song writer Freddie Mercury. In the days that followed, according to Sotheby’s, there were about 9.5 million views of the sale on TikTok. The entire collection, which ultimately brought in $50.4 million, created a new community of online enthusiasts.

“Incredible!’’ one wrote. “Love watching these … as if I have two pennies to rub together.”

As the bidding heated up and the numbers rose, so did emotions:

“Am sat here eating beans on toast because my electricity bill is so big. It’s either eat or heat. World makes me sick.’’

Another declared the sale a “vulgar display of wealth.’’

But social media has developed a new group of celebrities in their own right: Auctioneers are frequently being recognized on the street or in their local supermarkets. Facebook has a group of fans of Oliver Barker, the Sotheby’s auctioneer, who call themselves the BarkerHeads.

“Who is the auctioneer? ❤️❤️❤️,’’ read one online post, referring to Barker.

“I love watching this,’’ wrote another. “But I want to reach into the screen and fix his bowtie.’’