It continued and grew louder sporadically throughout the pregame workouts.
And it reached thunderous levels when John Maine threw his first strike, recorded his first out, struck out his first batter and retired the side in order in the first inning.
Playoff baseball always generates a different vibe to any stadium.
And on Wednesday at Shea, things were no different as the Mets hosted Game 1 of the National League Division Series, only the second time the Mets have had the first playoff game at Shea Stadium. The crowd of 56,979 proved to be the largest Division Series game crowd at Shea (five games: two in 1999 and two in 2000).
Yes, things felt different than just any old regular-season game.
Maybe it was the F-16 fighter jets making a practice flyby over the stadium during batting practice.
Or the exorbitant amount of television trucks that lined the exterior of the stadium.
You could sense it with the noticeably larger contingent of New York Police Department personnel on hand, roaming the grounds.
And you could tell with the appearance of several celebrities, including Ron Howard and Ray Romano, who both chatted with Mets chief operating officer Jeff Wilpon during batting practice. Grammy Award-winning saxophonist Branford Marsalis performed the national anthem while Mookie Wilson, a member of the 1986 World Series champions, and Jerry Koosman, a member of the 1969 World Series champions, threw out ceremonial first pitches.
The Mets were finally back in the playoffs after a six-year absence.
"Oh yeah, this is great. This is real special, fun, exciting," said a smiling David Wright as he surveyed Shea during batting practice, pointing to the 2006 NLDS logo painted on the field, and to the red, white and blue banners that hung along the lower and upper ring of the stadium. "This is what it's all about."
The last time a playoff game was played at Shea Stadium was Game 5 of the 2000 World Series, when the Mets lost, 4-2, to the Yankees in front of a sellout crowd of 55,292.
For some reason, though, this year's appearance brings with it a heightened sense of anticipation. Many fans attribute that to the type of year the Mets experienced this season.
"It's about time," said Victor Marchand, a Snapple delivery driver who grew up in Queens. "This is the best. Even though we lost Pedro [Martinez] and El Duque [Hernandez], we still have a team that can do things in the playoffs. And we showed it throughout the year."
A sellout crowd filled Shea Stadium again in Game 1 of this year's NLDS, and it hardly went unnoticed, especially by Tom Glavine, a frequent visitor to the playoffs with the Braves.
"It's crazy here," said Glavine, who will start in Thursday's Game 2. "I mean, you play a game here in front of a packed house or you play a game at Yankee Stadium in front of a packed house, it's the epitome of New York. There's energy, excitement, craziness; all that is boiled into what's going on.
"You know, our fans here have been great all year long. It's just a great atmosphere. They're into it. They know what's going on. They understand the game. They understand the situations. You know, if the true meaning of 'fan' is 'a fanatic,' that's what these people are; they're fanatic about their baseball and certainly about their baseball teams."
Throughout the game, whenever Maine or the Mets' relievers recorded an out, the always-loud Shea Stadium erupted, and the place reached bedlam when the Mets scored runs in the fourth, sixth and seventh innings, even louder than the aircraft that normally fly overhead out of nearby LaGuardia Airport.
Playoff baseball fever was alive and well, loud and crazy at Shea.
And perhaps one sign held by a fan dressed in a Mets jersey with blue, orange and white colors painted on his face told it all: "Travel plans -- $75, Playoff tix -- $300, Mets baseball in October -- Priceless."
The Mets hope to add one more line to that poster: "Winning in the playoffs."
But from the colorful signs and loud signs of it all at Shea, it all seems a given.
Chris Girandola is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.