Under The Hood: An Inside Look At HDR Audio Coming To Rocket League

August 8, 2019     Developer News  
Under The Hood: An Inside Look At HDR Audio Coming To Rocket League Image

There are just 10 seconds left in a tied game. Your teammate has possession, and passes it your way from the wall. You place the shot above the backboard where your opponent can't reach it, launch your car into the air with your remaining boost and follow up the backboard shot with a perfectly placed goal. The Goal Explosion ignites as time expires. The exhilaration is nearly tangible. But meanwhile, there are hundreds of sound effects occurring inside the game that supplement all the excitement of the moment: the siren, the announcer, the crowd, and that only scratches the surface. In moments like this, it may be easy to overlook the sound of Rocket League, but these sounds are an essential part of the experience.

The audio team at Psyonix works tirelessly on the sounds within these moments so Rocket League is able to achieve maximum levels of hype. Recently, the team that consists of sound designer Stephen Lichota, technical sound designer Miles Flanagan, and audio director Mike Ault has been hard at work on bringing High-Dynamic Range (HDR) Audio to the game. In today's world of 4K screens, the term "HDR" is usually reserved for vivid imagery on televisions, but it's also a part of the audio world. HDR Audio may share the name of HDR imaging, but it's a different concept entirely. While you need an HDR television to enjoy HDR programming, HDR Audio doesn't require any additional hardware and is specifically designed for video games. It enhances the mix of the audio so players will be able to more clearly hear the sounds that are important in the moment. That's the simplest way to describe this audio system that is anything but simple.

"HDR Audio is one of the hardest things to explain," says Stephen. "Even when we're constantly working with it, it can still throw your brain for a loop. Normally, you have a fader that you can adjust to make certain sound effects louder than others. It doesn't quite work like that in HDR Audio. It doesn't make sound louder. Instead, it makes other sounds quieter so there's an emphasis on specific sounds. So, then you're trying to listen for the things that the system is altering."

That's essentially what Rocket League's upgrade to HDR Audio is going to do. The sounds that are more important will be prioritized in a way so that they can be heard more clearly when they happen. "The whole goal is for you to hear what you want to hear the most," Mike explains. "So, you hear other cars, and you hear positional information better like where the ball is. Extra sound effects like crowd and ambience are moving out of the way. It all gives you a cleaner sense of the game."

This new sound mix didn't happen overnight. HDR Audio was attempted in the past, as early as the game's Neo Tokyo Arena release in 2016. But, that audio overhaul came with some growing pains. The world of audio engineering is not an exact science. There's only so much testing you do before the game is being played in online conditions. It's nearly impossible to recreate every combination of audio cues that could possibly happen in any given match. Plus, each update with new Boosts, Arenas, Battle-Cars, and Goal Explosions adds to the ever-growing library of sound effects.

"Rocket League is in its fifth year," Mike says. "There's so much sound-related content when you consider boosts, crowd noise, engine audio and so much more. Then, you stack 20 or 30 of those sounds at any given time. It can be pretty daunting to find where something is sounding wrong."

In addition to that challenge for the audio team, there's the issue of players experiencing the game's sound in vastly different environments. Some players rely on speakers built into a TV or monitor, while others may have high-fidelity sound systems. Most players, however, use headphones during their gaming sessions. In the past, Rocket League's audio mixes were primarily designed on top-notch sound systems, but that's not how most people are listening to the game's audio. The HDR Audio update is the game's first audio mix that was designed with a focus on headphones.

"When we did our last mix, we were doing it in one of our rooms in super high fidelity and listening to the audio at a louder volume than our community listening at home at night could realistically reproduce," Mike explains. "We created a very dynamic mix that we thought sounded fantastic. The vast majority of our players don't play Rocket League that way. So, rightfully so, we got a wide range of player feedback. This time, we took every step we could to recreate listening situations that our playerbase commonly experiences."

Throughout the development of this mix, the team played different games that handle dynamics in various ways. One game that stood out as an audio benchmark was Rainbow Six: Siege. According to the team, the sound design of Siege stands with its range dynamics of tensely quiet and bombastically loud states. Miles says that while this design can help guide the direction of Rocket League, Rocket League is a different beast entirely. "In Rocket League, you're driving a car that's accelerating and boosting nearly all the time," he explains. "That's essentially the only state of play, whereas Siege has two very different general levels of audio. It's a different case, but we can definitely take some useful cues from Siege."

One of those cues is to bring adjustable Dynamic Range Controls to Rocket League in a future update after HDR Audio hits the game and the team is able to monitor player feedback.

Once HDR Audio rolls out with the next update, the best advice Mike can give: have an open mind when you hear the changes for the first time. "There's this phenomenon in the audio world called 'temp love,'" he explains. "It says that people get attached to what they're used to. We're asking people to give it a chance. It will sound different. If it didn't sound different, then it defeats the purpose of remixing the audio. We genuinely feel that this is a major improvement and hope people approach it with an open mind. We're looking forward to hearing community feedback and using that to create the best possible listening experience."

Look out for HDR Audio in Rocket League's next update scheduled for August 27.