Extreme Cold Poses Extreme Challenges for Audio Teams
Very low temps hamper people and equipment producing both broadcast and in-venue sound
The St. Louis Blues’ 6-4 defeat of the Minnesota Wild in the 2022 NHL Winter Classic at Target Field in Minneapolis on Jan. 1 broke a record, the kind that only hockey can: it was the coldest outdoor game in NHL history. The temperature at Target Field was -6 F at puck drop, falling to -10 F as the game went on, with wind chill hitting the negative 20s, according to the league. It beat the previous record of 0 F set in 2003 in Edmonton, AB.
That kind of cold was potentially dangerous for the 38,000-plus fans who braved it to watch the event in person: extreme cold like that can cause frostbite in less than 30 minutes. The venue heated the teams’ benches and penalty boxes, even the ice itself to let skaters get traction.
As bad as the cold is for people, it’s not all that great for the audio equipment used for sports broadcast or in-venue sound. With two more outdoor-stadium NHL game broadcasts still on the schedule and the Winter Olympics looming, here’s how some broadcast-audio pros tackle the cold.
Watch Your Batteries
Veteran NFL and NBA A1 Dave Grundtvig has mixed Chicago Blackhawks hockey locally and NHL games for Fox Sports when the network had the franchise in the 1990s. He notes two key elements of broadcast audio particularly affected by bitter cold: cabling and batteries. The former is vulnerable to cracking and brittleness, sub-zero temperatures can affect its ability to propagate the signal at its full bandwidth, and its connectors corrode faster when exposed to a combination of moisture and freezing temperatures.
Batteries, meanwhile, notoriously drain much faster — as much as 60% faster — in very cold weather. Lithium-ion batteries, widely used in wireless bodypacks, work by discharging their electrical current as individual lithium ions that move through a porous graphite solution from one end of the battery (the anode) to the other end (the cathode). Cold temperatures slow those reactions and can even shut the chemical process off completely. (Ironically, although all batteries discharge faster when used in very cold environments, old-fashioned zinc-carbon batteries hold their charge better when stored at lower temperatures.)
“That’s a big issue for a lot of battery-powered equipment,” says Grundtvig, noting that the wider use of RF transmitters in sports now means lots more battery use. “Lithium batteries are better than the [carbon] kinds, but they’re still subject to diminished performance in the cold. And even some [AC-]powered gear has been known to fail when it gets really, really cold.”=
Temperature Affects Tonality
In-venue sound is also affected by very cold temperatures, particularly in the upper frequency ranges.
“Temperature definitely influences sound propagation, which needs to be addressed through equalization when the system is being set up,” explains Justo Gutierrez, director, AV and sound, sports and live events, Diversified, a provider of media-technology solutions. “The other challenge with the Winter Classic is adapting sound systems in existing non-hockey venues to work in conjunction with the sound systems that are brought in for the event — much like the way they are used when music acts perform in sports venues.”
Sound systems brought in for events like the Winter Classic are often integrated into the venue the way a music-touring system is: the visiting array is designed to cover the event’s particular seating configurations while the venue’s installed sound system covers upper-bowl seating.
Gutierrez, who worked on the 2012 Winter Classic at the Philadelphia Phillies’ Citizens Bank Park when he was with a different firm, adds that systems installed and commissioned in one season can react differently when the temperature changes drastically.
“If you tune a system in February and come back and hear it in June,” he notes, “you’ll notice the upper frequencies might sound more pronounced, and you’d want to dial them back. Other considerations include humidity. Touring systems now build algorithms into their processing that can measure and account for humidity and temperature and adjust the system for it. That’s going to become more common for installed sound, too, now that more [outdoor] venues are being used year-round.”
Keeping It Quiet
The NHL Winter Classic presents one of the best opportunities for a hybrid broadcast/live audio experience. At the Discover 2022 Winter Classic in Minneapolis, that was especially true as Target Field’s interior geometry created the need for a unique sound-system PA design.
According to Dan Gerhard, who designed and mixed the PA sound, the high outfield fence allowed the audio team to keep the PA system standing in place, rather than having the arrays tilt down during play to keep them out of sightlines as has had to be done for past events. (The infield was a bit more challenging, but splitting the PA elements there into two arrays solved that.) That extra effort was worth it, he says, because the field-audio team was able to deliver the ice effects — skate blades on ice are to hockey what sneaker squeaks on the court are to basketball — to the fans in the stands, along with bowl announcers and music stems from the PA. (Says Dan O’Neill, SVP, arena and event operations, NHL, “The sharing of the audio stems back and forth between broadcast and the live event made the ice effects available to the PA design.”)
“The sound was fantastic,” says Gerhard, “both the music and the effects.”
Extreme cold has more mundane challenges, too. Because the morning of the Minneapolis Winter Classic started out at -15 F, the field audio team had heated tents set up to keep both themselves and the fiber cabling they were running supple enough to work. However, the warmth came from propane heaters whose fan noise could rival the level of the monitor speakers inside.
“At first,” Gerhard recalls, “I said, ‘Hey, guys, I can’t have these heaters; they’re just insanely loud,’ before I realized I still absolutely needed them. It was just too cold not to use them.”
The solution was to run an electric line to the tent and add four electric heaters whose fans were considerably quieter, using them in place of the gas heaters when the crew needed to monitor critically. The fans still made some noise, however, so Gerhard would periodically duck outside the tent to make sure what he was hearing on the monitors accurately reflected what the PA sounded like.
“When you’re working in that kind of cold,” he says, “everything just takes longer and is harder to do.”