NBA Returns: Audio in the Bubble Features Mics From Floor to Ceiling

Embedded mics in the court and thorughout the arena create ‘a more organic spatial experience’

Describing the audio infrastructure as “the most challenging and complex” ever undertaken for an NBA season, Dave Grundtvig, lead A1 for Turner Sports’ coverage of the league’s compressed and strange season, is still tweaking the games’ sounds over a week into play.

Dave Grundtvig, lead A1 for Turner Sports’ coverage of the NBA season, shows off contact mics.

“We’ve never had anything like this before,” he says. He is supervising a larger array of microphones than ever deployed for NBA coverage, as well as a complex new audio element in the form of artificial crowd sounds pumped into the three arenas in Orlando, where the season is being played out. “It’s like mixing audio on a sound stage, one that we partially built ourselves.”

That comment is a reference to one particular array of microphones, hand-built by Grundtvig, working with Alex Berman, senior manager, technical services, NBA, and Dave Bjornson, principle, Hear Corp., a Pittsburgh-based broadcast-integration company. The mics are embedded under the floors of all three basketball courts. The games are being played in a so-called COVID bubble spanning three venues at Disney’s Wide World of Sports (WWoS) complex: The Arena, the main national-telecast court and site of Conference Finals and NBA Finals; HP Field House, used for the regular season to second round; and Visa Athletic Center, for games broadcast exclusively by regional sports networks.

Mics Under the Floor

Each of the three courts has 32 contact transducers screwed into the underside of the panels that constitute the court flooring.

Each of the three courts has 32 contact transducers screwed into the underside of the panels that constitute the court flooring, their arrangement based on experimentation during scrimmage games ahead of the season opener on July 30. Grundtvig had spent the previous three weeks in Orlando wiring and tweaking placements under the floor, mapping them using Vectorworks drawings supplied by the league. That was followed by sonic adjustments to be able to distinguish sneaker squeaks from ball bounces.

The embedded microphones provide extremely realistic court sounds for viewers.

“The thing about these contact mikes is that they don’t pick up audio; they pick up vibrations, because energy transfers better through a solid than through the air,” he explains. “These mics are basically hot all the time. Once we found the best locations for each of them and set the [input] trim and did equalization and dynamics shaping, such as gating and compression, they essentially mix themselves.”

In addition, two contact microphones are mounted behind the backboard glass, and two more are on either side of the rim next to the spring. These and several other microphones — there are a total of 40 contact microphones per venue, for a grand total of more than 120 throughout the complex — are routed to a pair of Soundcraft mixers and then on to the production trucks over a Calrec Hydra network on fiber and controlled via a laptop. Grundtvig estimates that the venues are connected with more than 27,000 ft. of cabling.

He says the embedded microphones provide extremely realistic court sounds for viewers and also make life easier for the networks: since they’re not carrying audio per se, they’re also not picking up any profanity. Other sounds of the game are picked up by shotgun microphones on handheld cameras, the basket mics, and short condenser mics on the scorers’ table. Ambient microphones high above the court round out the array.

Close up of a contact microphone attachment mounted under the court

The overall sound of the broadcasts differs slightly from past broadcasts, Grundtvig notes, with a more discrete and distinct array of effects sounds, from the court floor to the basket rims. An occasional voice comes through clearly when a player yells loudly, but the intentional lack of overall intelligibility keeps the sound safe for church. Actual voices are plentiful, though, from microphones on referees and coaches and, occasionally, on players, using the Q5X Player Mics.

“That’s kind of standard operating procedure that we’ve done before in a normal NBA scenario,” he says. “The new thing here is trying to cover the courts with the contact microphones: we can present something that is different and unique and have the whole floor covered and give this a soundscape that people haven’t heard before.”

Identical Layout in Each Court

Audio is laid out identically in each of three venues and is shared over two 56-channel splitters. Grundtvig says that allows crew members from Turner Sports; ESPN, which is also sharing the broadcast resources; and Firehouse Productions, which installed and is operating the venue PA systems; to move among them seamlessly.

The location of contact mics mounted beneath the floor of the court.

“If you go to [Channel] 22, it’s always going to be the same source, no matter what building you’re in,” he explains. “It makes life so much easier.”

(The two networks are approaching the venues very differently. Turner Sports’ A1s — Pat Thornton mixing in the Pavilion, Jeff Walker in the Visa Athletic Center — stay with one truck through all their games. ESPN, on the other hand, rotates A1s among the trucks assigned to the different venues. Scott Pray is ESPN’s main A1 in The Arena venue.)

“Because of the complexity of the trucks and the infrastructure and to try to dial in the particular sound of the building,” Grundtvig says, “on the Turner side, we are staying in a particular truck, a particular building.”

Live Sound

Another wrinkle in the NBA bubble is that the PA aiming is inverted, a 10-point line-array–type design that focuses the sound on the court instead of the seats (which are occupied by 300+ fans populating the 17-ft. LED videoboards lining three sides of the court via Microsoft Teams’ Together mode). The intent is to energize the players, who will hear authentically sampled NBA crowd sounds played back from servers operated by a pair of audio engineers following the action on court and acting as fan reaction proxies, plus one more mixer focusing on crowd chants and songs.

Contact microphones had their own assembly line.

These crowd sounds start with an ambient bed of what Hollywood film-audio mixers call walla-walla tracks: a concatenation of hundreds of indistinguishable voices. These form the foundation for the individual fan sounds, such as cheers, boos, and other reaction sounds collected from the teams’ games in previous seasons and controlled over a QLab audio interface.

The PA-system design creates zones around the venue and allows crowd-sound mixers to put different elements in different speaker zones at different times and volume levels, to approximate home and away fans’ responses to the action on the court. Grundtvig is sent a 5.1 surround mix of those sounds to mix to air.

“The beauty of that is, I can blend that sound with the ambient microphones that are picking up the sound of the room and send that to my audience,” he explains, adding that the natural delays of the PA speakers in different parts of the room enhance that effect. “It creates a more organic spatial experience, because I’m hearing the sound of the room versus just the direct sound of the live sweetening. It also lets us manage the PA level better on the air, because there’s no PA in [the seating area], so it’s not bouncing off the seats.”

Interestingly, Grundtvig notes, most of the feedback he’s getting about the audio is from the players themselves, reacting to a PA system that’s uncharacteristically designed around them: “Some want to hear more crowd, some want more music. It’s more interaction with the athletes than we usually have.”

One thing that hasn’t changed is the NBA’s desire for lots of low end on the music in the PA system.

“Absolutely, that hasn’t changed,” says Grundtvig. “And, just like with any NBA arena, a high-pass filter is always your best friend.”