How audio in H1Z1 helps create a post-apocalyptic mood

Audio is probably one of the most important, under-appreciated aspects in video games. That's probably how it should be — you shouldn't notice good audio; it should just seem like a natural part of the game.

"Game audio is one of those jobs where if you do it correctly, it's rarely noticed," admits H1Z1 Technical Architect Greg Spence. "But if it's missing or done poorly, the game can really lack immersion.  When you first think of game sounds, things like footsteps, weapon noises, vehicle sounds, and ambient audio come to mind.  So much goes into making these sounds seem realistic beyond just choosing an audio file to play.  Taking into account your surroundings, whether you are inside or outside, what type of ground you are on, time of day, and even weather can play a big part in the final thing you hear."

Spence, whose primary focus after joining the H1Z1 dev team was on the melee and grappling system, has since taken over the audio system, working with the audio engineers to bring this post-apocalyptic world to life. In the latest H1Z1 blog post, he shared with us three aspects of audio — sound effects, environment sounds, and ambient music — that help set the mood in H1Z1.

This video shows an example of gunshot sounds adapting to your environment. "When you're outside on a nice sunny day, and decide to fire off some rounds from your assault rifle, you expect to hear those shots ringing from the mountains and valleys around you.  The outside air makes the gunshot sound a specific way," Spence explained. "Now take that same assault rifle and go indoors.  The sound should be quite different.  On the game engine side, we mark up all of our terrain buildings with volumes and flag those volumes to indicate that you are indoors."

"Whenever your character enters or leaves one of those volumes, we tell the audio SDK whether you are inside or outside.  It's now up to the audio engineers to use that data to enable or disable affects.  These effects can be volume changes, reverb, echo, high/low pass filters, or just about anything they want to do.  It gives them an amazing amount of flexibility to be creative."

"Creating an immersive environment is what H1Z1 is all about. We have day/night cycles and weather changes that play a big part in shaping your environment. Ambient sounds also need to reflect these changes; so how do we do that? Supporting day and night is now as simple as passing the time of day to our audio SDK and letting the audio engineers have fun," Spence said. "We update the time value every game frame and the audio engineers can decide, based on that value, when to fade between different audio tracks."

H1Z1 currently has four different tracks that play through a 24-hour period. Daytime ambient sounds simulate wind movement and birds, while night time brings in crickets and occasional wolf howls.

And lastly, there's the music of H1Z1. The goal with music, according to Spence, is to stir emotion, build suspense and excitement, and sometimes warn of impending danger. In H1Z1, certain points of interest in the world will queue certain audio systems. The video below shows off some of those music queues.

Spence notes that combat will also drive music, and that music in H1Z1 will adapt to the direction of combat, "getting more suspenseful as you take more damage or attract more aggro." Music can also reflect "a triumphant ending or signal the end of your character."

H1Z1 doesn't yet have an early access date for PC, or PS4 for that matter, but we can see each week through these blog posts that progress is being made.