NEW YORK (AP) — The U.S. Open is loud. “Insane loud,” 2022 semifinalist Frances Tiafoe called it.

There are the planes. The trains. The music at changeovers — they don’t play “Danza Kuduro” by Don Omar and Lucenzo or “Move Your Feet” by Junior Senior at Wimbledon’s Centre Court, the way the speakers blared during Coco Gauff’s first-round victory at Arthur Ashe Stadium on Monday night.

And there are the spectators, who do not necessarily adhere to the sort of decorum often associated with tennis. They yell and whistle and applaud and get especially rowdy at Ashe, a 23,000-capacity venue that is the largest at any of the sport’s four major championships and really helps make the U.S. Open the noisiest Slam.

“The biggest stadium in our sport, the loudest stadium in our sport,” Novak Djokovic called it after winning there Monday. “It’s the size. It’s the echo because of the roof construction. It’s everything combined.”

When a big star is on that court or when an American is competing, the roars get wild enough. When it’s someone like Gauff, who fits both categories, you get what happened Monday. They applauded faults by her opponent, Laura Siegemund, and jeered when she spoke to the chair umpire. By the time the German’s news conference rolled around, Siegemund was in tears, saying: “They treated me bad.”

Add in a $150 million retractable roof that seals the place and keeps all of that sound inside and, well, let Tiafoe describe what it was like to face eventual champion Carlos Alcaraz at Flushing Meadows a year ago.

“I’ve never been in an atmosphere that loud in my life,” said Tiafoe, a 25-year-old from Maryland who is an entertainer at heart and enjoys riling up the folks in the stands by shaking a fist or waving his arms. “It was one of the craziest atmospheres I’ve ever been in. Like, 23,000 people in there felt like 23 million. Everyone was just going nuts, and everyone was drunk and it was just awesome.”

The fans at the U.S. Open are definitely more noticeable to players than those at Wimbledon and the French Open, in particular.

“Oh, they’re noisier, for sure,” said Caroline Garcia, a French player who reached the 2022 semifinals in New York. “In tennis, we are used to it being pretty quiet during the points. … Maybe it’s because the stadiums are huge here and people are used to going to watch sports like basketball, baseball or American football, where they can chat or shout. The culture around it is different.”

Which means, in some cases, 2016 U.S. Open champion Stan Wawrinka explained, “You need to adjust, a little bit, your focus.”

There are ringing cellphones. Crying children. Then throw in the occasional grinding of the roof being closed or the humming of an air ventilation system.

“That’s why I would have struggled in this stadium,” 18-time major singles champion Martina Navratilova said about Ashe.

She won on every kind of surface and setting in her Hall of Fame career, so the idea that the environment could affect her is hard to imagine — until she explains the importance of sound to a tennis player.

“First you hear the ball and then you see it. … That helps you track the ball,” Navratilova said. “When you don’t have that sensory input, it’s like, ‘Where is the ball?’”

The ruckus extends well beyond Ashe.

Planes are early in their climb as they depart LaGuardia Airport less than 5 miles away. Passing subway trains can be heard as can honking car horns outside adjacent Citi Field, home of the New York Mets.

It’s not possible to eliminate all of that — or the sirens that bothered Nick Kyrgios last year or the thwack of rain drops that Andy Murray once complained about pelting the shut Ashe roof.

Tennis fans are expected to hold their applause and yells until points are over, but it’s hard to ask thousands to remain silent — try as chair umpires might, repeatedly asking for “Quiet, please,” or admonishing, as happened during Gauff’s match: “If you could keep your voices down, that would be greatly appreciated.”

Navratilova compared it all to attempting to compete with headphones blaring music into your ears.

“You’re going to be lost,” she said.

Or, at the very least, confused.

That’s what happened to Aryna Sabalenka during a match last year. She demanded an explanation from the chair umpire when action continued after she clearly heard a voice scream “Out!” at the far baseline.

The answer: The person yelling out wasn’t an official. It was a spectator.

Calling the match on ESPN, Rennae Stubbs chuckled and delivered what could be a warning for the two weeks ahead: “Welcome to New York.”