Aloha gearheads. My name is Mark K (not to be confused with Mark P), and I'm one of the strange audio folk that wander the corridors of Gearbox HQ. While I'm officially the audio lead on Borderlands, right now I'm spending a lot of my time helping out the Hell's Highway team, and my primary concern this week is the weather.

So the location is Veghel, Netherlands, and the weather is bad. Stormy, in fact, and it's my job to ensure that all of the lightning flashes and raindrops make noise. The trick to making rain believable is to know that the rain itself makes no noise, it's all about the surface the rain is falling on. With that in mind, I've been working my way through the town, putting rain sounds on the various surfaces you will encounter as you lead your squad through. As you move closer to cars, you will hear the rain pinging on their metal bodies. As you approach a troop carrier, you will hear the rain bouncing off the tarp covering the back of it. If you're under a wooden overhang, you will hear the rain beating above your head.

Additionally, I've had to teach the audio engine how to mix all of these sounds. By telling it which sounds are "outside sounds" and which are "inside sounds," then telling it what to do, I've created a system that mixes the audio based upon your location. So when you walk into the shop on the corner, it lowers the rain sounds outside and raises the inside sounds (rain beating against the windows, rain in the doorway, etc). When you walk back out, the outside sounds will come back up, and if you're playing with a 5.1 speaker system you will hear the sounds begin in the center channel and wrap around you. Every time you move through a doorway it will look at where you have been, where you are going, and adjust all of the sound levels accordingly.

The biggest challenge with making this thunderstorm, however, is making it sound great without using a lot of space. Through clever placement and intelligent realtime processing, I can reuse a lot of the same sounds without you, the player, ever hearing the difference. In fact, as it stands, if I were to string every piece of this thunderstorm together, the total amount of time would be 1:40, which is less than half the length of the Ben Folds tune I'm jamming as I write this.

Being obsessive about memory management is what allows us to squeeze so many great sounds into the game. In a typical playable sequence, you'll have the environmental sounds, interface sounds for the menu and tactical map, all of the dialog your squad mates and enemies use as you interact with them, the vehicles, weapons and destructible objects. That's a lot of stuff, and memory is at a premium (especially on consoles), so we learn how to make every last sample usable.

So that's been my week: making rain and watching the memory. I'm beginning to think I should bring a raincoat to work.

Discuss the sounds of Hell's Highway further with our devs and community on the forums !