The Sounds of Silent NFL Stadiums

The person in charge of what you hear when you watch a football broadcast is called an audio mixer. It’s an apt title, since the sounds from the stadium that come into people’s living rooms are like the ingredients of a recipe: They’re collected in raw form from the field, the sidelines, and the stands; measured out; and mixed together. The final product delivered to viewers represents what they’d hear if they were at the game themselves, but it’s not an exact replica.

A good audio mixer can make viewers feel like they’re close to the action by letting them clearly hear the quarterback’s clap that breaks the huddle or audible calls at the line of scrimmage, even though no one in the stands can actually hear these things. Play calls, a hit, or a player’s cry that might be wince-inducing on a quiet practice field blend into the game-day atmosphere. The sounds you hear during a television broadcast are really a highly produced and edited version of the game, one that reflects the priorities of the league, satisfies the TV networks that pay billions of dollars for the broadcast rights, and provides fans with a pleasant viewing experience for one of the most popular entertainment products in the world.

One of those key ingredients is the fans in attendance. The noise made by a packed house changes how teams operate on the field and how viewers react to the action. It helps offenses protect their play calls from defenses and creates moments of heightened activity and tension that lets broadcasters tell the story of the game. That story will be dramatically different in 2020, at least at the start of the season. Twenty-six teams plan to play their first games of the season without fans, a result of the COVID-19 pandemic. By now, fans have become accustomed to the absence of crowd noise; the NBA has, somewhat successfully, created a virtual atmosphere for its games, with images of fans’ floating heads visible on the broadcasts. The NFL is hopeful that, eventually, fans of all teams will be able to be in the stadiums in a limited capacity, but the league has prepared for an augmented viewing experience that will be unlike any other in its history.

The NFL told teams last Thursday that they will provide them with a loop of prerecorded crowd noise designed by an audio engineer to play over the PA system in their empty or partially filled venues this season, at least to start. Each loop is different, specifically designed for each stadium. Players and coaches will hear it over the speakers, and the league will give a different feed of prerecorded sound to broadcast networks through a special feed. The fake crowd noise will start at kickoff and will be played at 70 decibels, with the league monitoring to make sure that even when the recording is combined with foghorns, whistles, or other announcements that typically come from in-stadium PA systems, the noise never goes above 75 decibels.

For context, 75 decibels is more of a Cincinnati Bengals home game than a Kansas City Chiefs one.

With a packed house, an NFL crowd can maintain 115 decibels when the home team is defending the red zone, or when the offense scores a touchdown. Brad Ricks is an audio engineer who has done sound design for multiple NFL stadiums. He says during an important drive, stadiums usually stay above 105 decibels. That’s as loud as a typical rock concert or a Boeing 737 at takeoff.

“The quarterback has to scream,” Ricks said.

Ricks said that he’s been asked to build PA systems that can get louder than the crowd, so that an announcement could be heard over the screaming fans. He responded that not only would it be prohibitively expensive, but the Occupational Safety and Health Administration would also consider it dangerous. Crowd noise can get so loud because it builds gradually and our ears adjust, the way they do when you turn your car radio up while driving on a busy highway. Having an equally loud PA system would be like turning the car back on in the garage the next morning and having the same volume.

The pumped-in sound provided by the league will create a “baseline murmur,” according to the memo sent to teams, but it won’t re-create regular game-day atmospherics. Why does this matter? If less noise makes calls at the line of scrimmage easier to overhear during games or on TV, it could change the competitive balance between defenses and offenses. Former NFL offensive lineman Joe Thomas told me that defenses can already pick up a lot of offensive communications, but that this year, he thinks “there’s going to be so much more sign-stealing, for lack of a better word.”

After 2011, Thomas told me he started hearing from defensive players that they spent more time watching TV broadcast tape of their upcoming opponents than the film distributed by teams known as All-22, which shows the entire field but has no sound. That was the year the networks started picking up sounds at the line of scrimmage using a microphone worn by a guard or center instead of the umpire. (Think of Tom Brady yelling “Rita! Rita!” or calling out the Mike linebacker before running a play.) The umpires had previously been able to pick up good sound for the broadcast because they were typically stationed behind the defense at the start of each play. The problem was the umpires kept getting run over during the play, so the league repositioned them behind the offense and started mic’ing up a center or a guard instead.

This was a great development for two groups of people: TV viewers and NFL defenders. Broncos outside linebacker Von Miller, drafted in 2011, said he’s always preferred the game tape from the TV broadcast and marveled at how much he can pick up from it.

“Even during our home games, you can still overhear some type of stuff,” Miller said.

An experienced defender doesn’t need to hear every word, either. Thomas described it like code-breaking: more about picking up patterns than hearing specific calls. If that’s already happening at 100-plus decibels, it will likely happen even more at 70.

“If you’re calling the same thing in the huddle three, four times, as dumb as defensive players usually are, they’re going to figure out what your play is after a little while,” Thomas said. “There’s going to be so much more sign-stealing.”

What’s an offense to do? Thomas thinks every team may wind up using a silent count this season if it turns out that calls at the line of scrimmage cut through the 70-decibel murmur too easily.

“It’s going to be a whole game within a game this year that nobody has even considered because they haven’t had to,” Thomas told me.

Well, some people have considered it. Patriots offensive coordinator Josh McDaniels told me he plans to spend more time this season self-scouting New England on the TV broadcast tape. It’s easier to avoid giving signals away in the first place than to have to change them.

“You can’t change your language, you know what I mean? It’s like, if we know English we can’t teach them Spanish before Week 1,” McDaniels said.

The difference between Laser and Larry on a play call can be the difference between a 5-yard run and a defensive end running directly at the quarterback. It might prove too easy for players to get words mixed up if they’re constantly switching.

Coaches will also be worrying about themselves when speaking (read: yelling) on the sidelines. The NFL typically mandates that the microphones attached to cameras that travel across the field be turned off when the cameras are between the 35-yard lines to avoid picking up conversations happening around the benches, but that distance is sometimes not enough to avoid overhearing conversations. Crowds haven’t always made enough noise to protect everything that’s said on the sidelines, and those accidental windows into private moments—strategic or otherwise unfortunate—could become much more common this year.

For those producing the broadcasts, losing the crowd is like losing a character in the story they are trying to tell live and in prime time. When the Chiefs were mounting the largest comeback in team history against the Texans in last year’s playoffs, you could feel the crowd’s building fervor in Arrowhead Stadium through your television screen. When defensive end J.J. Watt fractured his tibial plateau, a season-ending injury, in 2017, the sudden hush that fell over the stadium captured the seriousness of the moment.

“I always think of football as a much more vocal environment from fans versus, like, a baseball or even a basketball game,” said Jimmy Platt, ESPN’s director of Monday Night Football, who will oversee the network’s broadcast from the production truck each week.

For a typical MNF broadcast, ESPN has 23 to 25 microphones in use all around the stadium and on players and announcers. There are four parabolic microphones—the ones that look like big, clear satellite dishes and are held by operators standing around the field—to pick up on-field noise, plus microphones on cameras, other parabolic microphones around the higher levels of the stadium and additional microphones on players and announcers. Wendel Stevens, NBC’s longtime A1, or lead audio mixer, for Sunday Night Football, told me that for an SNF broadcast there could be as many as 50 microphones ready to use—though some of those, like sideline reporter Michele Tafoya’s backup wireless microphone, don’t typically get used.

Among the people you don’t see during a game, but who heavily influence what you hear is a sub-mixer, whose job is to mix the sounds of the crowd with the field-level noise. They then feed that mix to the A1 who combines that sound with the announcers’ calls and any additional elements like theme music or commercial-break outros to create the final product the audience hears. Mixers tend to think of all those sounds as layers to balance on top of each other. There’s the game itself, then the communication between players and coaches, then the noise of the crowd and the PA system, then announcers, play-by-play people, and analysts. Stevens told me that the broadcast crew is always the most audible top layer of a good mix, but that the voice of the crowd helps tell the story of the game.

“It has these dynamics and these highs and lows,” Stevens said. “Home team gets the ball—if Tom Brady gets the ball in New England or, back in the day, Peyton Manning has the ball in Indy or Denver, it was like church because fans knew that these guys worked a lot at the line of scrimmage. You could hear everything.”

Without large crowds, broadcast teams are not going to try to re-create that fluctuating symphony. Stevens and Platt both said that one feature of a good mix is that the sound matches the picture on the screen—it would be odd for a viewer to hear an enormous crowd and look at a nonexistent one. Authenticity is one of their ultimate goals.

“Deliver what’s actually going on and happening there,” Platt said.

Piped-in crowd noise makes it difficult to do that. Sounds coming from stadium PA systems are harder for broadcast teams like Stevens and Platt’s to control because of how sound travels and reverberates. When sound waves come into contact with a soft surface, like a person, possibly one wearing a jersey or a puffy winter coat, they get absorbed and the sound dies down. When they hit a hard surface, like a plasticky stadium chair, they bounce around and sound more echoey. Many fans have gotten used to the effect of fake crowd noise pumped into NBA games recently, but if it sounded strange initially, this is why.

“There’s not going to be anything to absorb that, so you’ll hear an empty stadium, you might say,” said Ricks, the sound engineer. “Our ears will pick that up.”

The effects will vary from stadium to stadium. Sound will escape open stadiums more quickly, while domed stadiums will produce more of that spooky, echoey effect. Results will differ based on where the speakers that normally broadcast the PA systems are placed within venues, too.

There are three basic types of PA-system layouts in NFL stadiums. Domed stadiums—like the home venues of the Cardinals, Vikings, Cowboys, Lions, Rams, Chargers, and Raiders—amplify sound from above with speakers essentially hanging from the roof. Then there are the so-called distributed sound systems, where speakers are placed in intervals around the lower bowl of a stadium. Most open-air stadiums—including those of the Patriots, Jets and Giants, Eagles, Seahawks, Dolphins, Jaguars, Bucs, Titans, Broncos, Browns, and Bengals—have distributed systems. The last kind of setup, used by the 49ers at Levi’s Stadium and the Chiefs at Arrowhead Stadium, is called an end zone system, where all the speakers are placed at one end of the stadium.

Ricks says the stadiums with distributed systems should be able to pump in the prerecorded crowd noise and still sound relatively normal both from the field and on television. Since speakers are placed around the bowl of the stadium in distributed setups, the noise will be coming from roughly the same place as it would if it were sourced from real fans and will be evenly distributed around the stadium. The fake crowd noise in domed stadiums may sound a bit more foreign since the sound will come straight down onto the field and fans aren’t typically cheering from the rafters. The end zone systems are the hardest to adjust for since they provide just one concentrated source of sound. PA systems and announcers are often the nemeses of sound mixers because of their freewheeling interruptions, goofy sound effects, and penchant for classic rock (OK, that might just be my issue). “If I could find PA people and beat them with a wooden stick sometimes, I would,” Andrew Stoakley, audio mixer for the Toronto Blue Jays, told Vox in 2018. But now those systems will be responsible for far more than the occasional interjection—they’re providing the audible experience for the players, coaches, and the viewing audience.

That means home-field advantage might not be as valuable this season. The Chiefs, for instance, hold the Guinness record for loudest crowd roar inside a stadium, set with a 142.2-decibel output during their 2014 win against the Patriots—when Bill Belichick said “on to Cincinnati,” his ears were probably still ringing. This season, the placement of the Arrowhead PA system in one end zone could make the piped-in noise sound more noticeably different than real fans. Some players might not even notice much of a difference. Melvin Gordon signed with the Broncos this offseason from the Chargers, who spent their first three seasons in Los Angeles playing at Dignity Health Sports Park, a 27,000-seat stadium that hosts the L.A. Galaxy of MLS, and isn’t anticipating an adjustment.

“Bro, we didn’t have fans anyway,” said Gordon.

Typically, the closer fans can feel to the game, the better. Mic’d-up segments are usually a hit because they bring us into the huddle or onto the bench in a way that feels real and intimate, even though the snippets of conversation we end up hearing are heavily sanitized. The sheer number of microphones broadcast teams use during games and the technological feat of mic’ing up a stadium filled with upward of 80,000 people illustrates the desire to bring fans into all corners of each game venue. The results are incredibly effective, judging by the NFL’s cultural dominance. In 2019, 41 of the 50 most-watched American television broadcasts were NFL games, which speaks to the popularity of professional football in general and the ability of the networks to show games in ways that feel compelling, entertaining, and authentic.

Still, the audio mixers have to make sure things don’t get too real.

“What you hear on TV is this created image,” Stevens said. “If you go sit in the stands at a football game, you might hear whistles—you would hear whistles, I would think—and if somebody was tackled near you and you were in the lower levels, you might hear helmets collide. But you don’t hear the quarterback yelling, generally speaking. You don’t hear the contact at the line of scrimmage.”

Fans in the stadium also don’t typically hear the worst of the hits or the screams of pain from players when they’re injured. Thomas said that he was usually great at blocking out all noise during games except for calls from his quarterback or fellow linemen. One of those rare exceptions was when he heard then-Browns center Alex Mack’s leg snap at the bottom of a pileup during a 2014 game against the Steelers.

That’s not a sound the league or the networks want audiences to hear. Just like the audio technicians holding the parabolic microphones have to judge the path of the ball each time a quarterback throws it, sub-mixers and A1s have to make educated guesses on which microphones to turn on, off, up, and down during important moments, so they catch exuberance, but not agony or expletives.

“The league is our partner, and we have an audience to protect,” Stevens said. “You just try to, as much as you can, weed out the bad stuff along the way.”

Sound mixers will generally avoid opening a parabolic microphone on the sideline near a coach who happens to be in the midst of a helmet-slamming screaming fit. They’ll also turn the sound down on a player screaming in pain or avoid playing upbeat outro music over the image of one writhing on the ground. This probably creates a much more pleasant broadcast, but it does so by masking elements of the game that are unpleasant for audiences but are a regular occurrence for the players.

If NFL broadcasts resemble other sports broadcasts from empty stadiums, some things will get on air that the networks would probably prefer to have kept off of it. Even from venues where artificial crowd noise is used, more swear words than usual are getting picked up on TV, prompting both delight and pearl-clutching. Stevens said he’ll always have a good sense of humor about the inevitable errant sounds; during his last Super Bowl, an extra-tight uniform stretched over the microphone on a mic’d up linemen and led to errant squelching on the broadcast.

“I don’t know how to say this to put it in print,” Stevens said. “But it made it sound like someone might be expelling gas.”

Here’s hoping the sole sonic implication of empty stands and artificial crowd noise is unintentional comedy, but it’s likely to spur changes in how teams communicate on the field, how broadcast teams produce a live experience under drastically different circumstances, and potentially, even how fans relate to what’s often a brutal game. The roar of the crowd is a quintessential sound of football. Without it in its real form, we may really hear some of the other sounds for the first time.