You can put a roof on Arthur Ashe Stadium, but you can’t put a lid on every problem. At the U.S. Open Tuesday, there was the matter of losing so many second-round matches to rain on the field courts that Wednesday’s schedule calls for a fairly impossible 86 men’s and women’s singles duels across the National Tennis Center grounds.

And, while the retractable Teflon covering allowed business as usual with the Ashe docket, there remains an annoying unintended consequence of being sheltered from inclement weather.

Racket. Thoroughly un-tennis racket.

“Being honest,” top seed Rafael Nadal said of the roof’s retention of constant spectator babble, “is a little bit too much.”

Nadal, after taking control in the first-set tiebreaker, dismissed 85th-ranked Dusan Lajovic of Serbia, 7-6 (6), 6-2, 6-2. And Nadal insisted he didn’t “want to be the one that says it is too much noise.”

But he could be candid without being troublesome. And the truth is that the atmosphere in a closed Ashe tends to take the focus entirely away from the action on the court with a barroom hubbub that never lets up.

Aware of last year’s clamor in the roof’s debut tournament, the U.S. Tennis Association worked at repositioning air-conditioning units and other mechanical sources of loud buzz. But the crowd’s decibels, trapped indoors, remain strikingly high. At one point Tuesday, when the chair umpire asked fans to find their “seats, please,” the operator of a scoreboard text that assists the hard of hearing misinterpreted it to “Feet, please.”

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Nadal, being tactful, noted how “the energy and support of the crowd is massive. I enjoy it and I have unforgettable memories from this tournament and this court, because the energy is different from other places. But at the same time, under the roof, is too much. Because all the noise says inside. With the roof open, the feeling changes a lot.

“I understand it’s a show, at the end of the day, and I enjoy that. I feel part of this, but under the roof, we need a little bit more strict about the noise. The USTA makes an amazing improvement for the fans, for the players, for the TVs, for everybody with the roof, and now they can make it even a little bit better if they can control a bit of that noise.”

When the tennis center opened in 1978, and for several years before then-mayor David Dinkins worked out a plan with LaGuardia Airport to move takeoffs away from the Open, players complained that the jets’ din prevented them from judging the pace of shots off opponents’ rackets.

Now they are citing a similar hearing impairment with the roof closed, how it is “so difficult to analyze how the ball is coming when you are not hearing very well the sound of the opponent’s ball,” Nadal said.

The Australian Open and Wimbledon also play Grand Slam under roofs. So, noisier at Ashe?

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Nadal practically whispered.

“More,” he said. “Yes.”