The written contents of this article are essentially the raw script for the video. This article may get converted into a better to read format in the future.
“…You can never plan a success, but you know; Starting with a dent is a good start!” Magnus Walterstad
Mirror’s Edge is a strange game in so many ways. It was released during an international economic crash and it was overshadowed by other gigantic game releases, but managed to cultivate a large enough cult following to warrant a sequel. It also is largely responsible for the popularisation of parkour mechanics throughout the games industry!
Despite the unlucky circumstances surrounding the games release window, Mirror’s Edge is often referred to as a timeless masterpiece, a first person jump and run parkour game, which is often commended for sporting exceptional graphical fidelity, innovative gameplay and impeccable animations.
Game audio tends to fly under the radar and especially when it comes to Mirror’s Edge, I do not understand why. The game not only features great music, but also impressive dynamic audio systems and ambient sound design which goes above and beyond what an average player might expect from a linear action game from the late 2000’s! I hope I can showcase how special Mirror’s Edge truly is in this episode of Sound Design in Games!
[Intro -> transition into gameplay]
Mirror’s Edge takes place in a rather believable world which is quite similar to our own yet much cleaner and dominated by Bauhaus and Brutalist architecture. The game doesn’t lend itself to crazy science fiction soundscapes, sounds of mythical dragons or crazy high tech weaponry; It rather has to rely on familiar sounds we all know too well. Footsteps, rustling clothing, hands grabbing onto things, shattering glass, the sound of running past structures and people and to top all this off we have mundane city life soundscapes which you could only register as background noise going about your day to day life. Listen up, I want to show you something!
Movement; Basic movement #
[cut or transition into Half Life 2… maybe through masking?]
Welcome to City-17! We are here for a reason, mainly to showcase one rather boring aspect of sound design which you would never think about twice. Let’s get off this train!
[walks a few steps]
Did you hear that? No not the robot thing, the footsteps! Nothing to write home about, as is the case for most video games. You have a collection of alternative foot step sound effects which are triggered in a random pattern. Half Life 2 of course features different footstep samples for different surfaces as well. The footsteps are there and they work, but they aren’t quite as realistic as they do not take into account how Gordons feet interact with the ground… And besides, Half Life 2 relies more on its environmental soundscapes rather than a dynamic soundtrack and detailed sound effects of the player characters body, which you cannot even see if you look down! Besides the footsteps, we cannot actually hear Gordon Freeman; No friction between his legs, no rustling of clothing, no clinking from his HEV suit – Gordon doesn’t even seem to get exhausted over time judging by the lack of breathing. I’ve had enough of this future dystopia, let’s go back in time again!
[transition back to Mirrors Edge]
Here we are again in “The City”! Let’s take a walk.
[starts walking, could transition into running and sneaking, music off]
You might notice that the footsteps sound a lot more convincing, and instead of only hearing footsteps, you also can make out the friction and rustling of Faith’s clothing. This was necessary as for one Faith was fully modelled and more importantly, all you do in Mirror’s Edge is jump, run and climb, so an incredible amount of attention was put into making Faith sound real. Let us look and listen at the footsteps again. This time though, with as little ambient noise as possible!
[transition into UDK]
Welcome to… “Movement.umap”; A demonstration map I created in a day in order to showcase the movement sounds! It is not very pretty, but functional for this demonstration.
[sampler of sneaking, walking and running]
The interesting thing is that footsteps are actually composed of multiple sound effects! The movement sounds are played at specific keyframes of the animations and consist of a foot plant, foot lift and a cloth sound which originates from Faiths baggy pants at a keyframe when both legs touch each other in the movement cycle. This ensures that footsteps always sound accurate if the player decides to modulate their running speed.The movement also possesses an escalation system which dictates what samples are chosen for varying movement speeds. Different sounds for sneaking, walking and running exist to make movement feel even more natural and there even are appropriate sounds for Faith readjusting her body while turning around in place. For a game with an almost single minded emphasis on movement, going above and beyond with an area of the sound design like the footsteps, something an average gamer may not even take note of during their playthrough, actually greatly enhances the experience. In a game like Half Life 2, the focus is on the shooting and the puzzles, you most likely would not notice some repetition and simplistic design in the footstep sounds, for Mirror’s Edge, this kind of thing would have stuck out like a sore thumb, so I would say the time DICE put into this absolutely paid off!
Movement; Additional movement #
Wall runs also got their own footstep and foot release sounds! This is not the only part of the puzzle for making the movement sound great though, we also have interactions which involve hands touching different props, like Pipes, ladders, and various different surfaces hands have to touch in order for Faith to climb on top of them or vault over them, everything you could think of in terms of movement is accounted for, and that is great!
We also hear more interesting details in other movement options. Vaulting for instance is accompanied by whooshing sounds which I could only distinctively hear in my test map.
[Faith Vaulting showcase in Movement.umap]
There are also more details surrounding pipes! When swinging from pipe to pipe you can hear a distinct ring when swinging off the previous pipe.
[Showcase Pipe ringing]
Then we can also hear Faith struggle to hold onto the pipe after some time.
[Showcase Pipe strain sounds]
Movement; Breathing system
Finally, another addition to Mirror’s Edge was the escalation based breathing system. It is also based on the player character’s velocity. When idling the player hears long inhales and exhales through the nose. When gaining speed the breaths become shorter and when reaching a certain threshold Faith starts to in and exhale in long breaths through her mouth, which become shorter over time. When she comes to a standstill, the breathing de-escalates relatively quickly back to the long breaths through the nose.
All of these sound effects working together greatly amplify the experience of playing as Faith. It is clear that thanks to DICE’s efforts with the sound design, Faith can truly feel like a living, breathing person, a character audiences can get immersed to play as, something that is often lacking in other first person games.
Combat
For movement, animations and sound effects have to work together. The same rings true for combat. When fighting against a cop we have different sounds for punching an NPCs head or torso, so when Faith Punches the NPC the game plays the punching animation and when it reaches the specific keyframe that plays a sound, it checks whether or not Faith is hitting the head or torso or misses the punch all together and then plays the appropriate sound file for the attack.
[Small Melee Compilation]
Speaking of combat, guns are pretty much carried by sound design entirely, aside from the punchy and loud gun sounds, visually not much is actually happening. The guns might sound similar to guns from another game which sports way more shooting and no parkour at all.
[gameplay from BLACK]
The similarity isn’t coincidental! (Ben Minto,) One of the guys who worked on BLACK’s guns also happens to be the same person who handled foley recordings and creating the gun sounds for Mirror’s Edge. No custom gun recordings were done for Mirror’s Edge, instead they were designed by combining previous session material and library source. Some of the gun sounds were initially intended for BLACK 2, an unannounced and unreleased sequel, before finding their way into Mirror’s Edge. One giveaway for the gunshots not being real becomes apparent when taking a listen at the shotgun sounds.
[highlighting the FWHOP sounds of the shotgun]
This very certainly isn’t what a shotgun sounds like, but it is incredibly satisfying to use this gun for the sound design alone! The assault rifles and machine guns especially are incredibly loud and maybe even a bit distorted when fired, these weapon sounds are a key contributor to the tension of the game’s chase sequences, as enemies will be frequently shooting at Faith while in pursuit from behind her, the booming firing sounds create a clear sense of immediate danger for the player. They also add to a kind of power fantasy feeling when Faith manages to wrestle a gun from a guard and use it for herself, making them feel very powerful and maybe also a bit overwhelming for the player.
Realism is what many players expect from realistic looking guns nowadays, but it can be a bit boring. Gun recordings are a great option for games that revolve around shooting. Simulators like Hot Dogs Horseshoes and Handgrenades or Arma require realistic sounding guns, but there is nothing inherently wrong with Hollywood-esque sounds for firearms either. For Mirror’s Edge, I prefer Hollywood!
Ambience and the Runners Bubble #
Before we delve into foley there is another important thing to touch on which also hinges a bit on movement. Mirror’s Edge has a lot of ambience which like most other things in the game behave in a dynamic manner. One design principle for Mirror’s Edge was that any noise you hear in the game has a source. Air conditioning units make noise and some of them are broken and emit their own characteristic rattling sounds. Pipes have water running through them, the traffic can be heard throughout the city and certain locations also feature special soundscapes, like the storm drains section of the Jacknife chapter, which features many sounds of flowing and dripping water.
Ambience also has something to do with movement. First off, when Faith starts gaining speed, wind is added on top of all the other systems that relate to movement, but even the sound of different objects change depending on proximity and velocity of the player. The sound of an AC is perceived differently when standing right next to it idling when compared to running past it at full speed. When far away from an object, its sound blends into the noise of the city. The game modulates the sound based on proximity and of course at some point cuts a sound off and disables it completely when the player is too far away to hear it. There are also props in the game which are referred to as “dead objects”. Those objects do not emit any sounds by themselves, but depending on the velocity of faith, those objects can emit whooshing sounds when running past them. A good example for this would be the many kickable doors.
One drawback of the velocity based sounds emitted by dead objects, is if Faith herself isn’t accelerating, no sounds can be emitted from dead objects. This posed a distinct challenge for the sound designers in the train segment in which Faith jumps onto the roof of a moving train and dodges obstacles coming her way. While the player perceives Faith as standing on top of a moving vehicle, in reality the train is stationary and Faith is standing on a non moving object. The tunnel itself is built out of different components which spawn and despawn periodically in order to create the illusion of a train driving through a tunnel. Since Faith is not actually being accelerated, but the world around her is, a distinct system had to be implemented into that portion of the level, where objects around faith emit whooshing sounds when passing the player.
[Sound Demo, maybe also a zoomed out look to show the spawning and despawning with Cheat Engine tools?]
Another big aspect that cannot be ignored is sound occlusion. Occlusion means that sounds are blocked or muffled by other surfaces. Mirror’s Edge possesses a lot of faked occlusion, traffic being a good example. When standing at a ledge, you can hear a lot of traffic noise, but walking away from the ledge the sound of traffic is occluded more and more, making it less prevalent the further you distance yourself from the ledge.
[Highlight traffic occlusion]
(text or spoken) Notice how car horns are still audible away from the ledge but the sound of asphalt is non existent?
Or when walking indoors, the sounds from outside get muffled. The occlusion isn’t real, and that is apparent with how intense the shift in audio is when walking out of one area and into the next. Take a listen!
[Sound Occlusion demo]
The ambience reacts to the player and it contributes to a design philosophy called “The Runners Bubble”. This design concept explains what the runner should be able to hear in their immediate surroundings when navigating the environment at any speed.The concept includes ambient noises, music and also specific events that happen around the runner at all times. What sounds should be amplified and which ones shouldn’t overpower others? The experience of standing still in a corridor may not be as exciting as running past it, but both experiences feel natural as there are a lot of audio sources going off at the same time.
Other decisions have been made which stray away from realism and take over a functional role. To enhance the player’s awareness of runner enemies chasing after them, the footsteps of the Pursuit Cop enemies have been amplified to be heard clearly. This invokes stress in the player and lets them know how close Pursuit Cops are and from what direction they are approaching Faith from.
This greatly helps in ramping up the pressure compared to Faith’s previous encounters with enemies, as by the time the Pursuit Cops are introduced the player will be well accustomed to slow moving cops or SWAT teams that can never keep up with them as long as they don’t take a wrong turn; Suddenly coming into contact with hostiles that are able to keep up the chase consistently, with their footsteps always a short distance away, can send the player’s blood pressure through the roof!
From these examples we can see that achieving realism isn’t always the goal for a game’s sound design, and doesn’t need to be. As the name implies, sound is “Designed”, which means that the experience can be crafted to invoke emotion and provide function while being believable. Many times the sounds we hear aren’t actually produced with the exact same materials we would expect which is what Foley most of the time is about!
Foley #
[showcase game sounds -> fade in pictures of recording studio with appropriate sounds]
What looks like an incredibly messy garage filled with a lot of junk and recording equipment, actually is an ideal environment for Foley recording sessions! In order for the sound designers to be able to conduct their art, the studio is jam packed with props that reproduce interesting sounds. Grates, pipes and fences, instruments, cables, furniture and in the case of the particular studio in which the Mirror’s Edge Foley sessions took place, SVT in Stockholm, even a car is present in the middle of the studio. Any surface you would need to record for an urban parkour game is present, from glass to dirt, concrete, grass and gravel. Sometimes objects are even stacked on top of each other to create more nuanced sounds, or to dampen sounds which may otherwise include an unwanted texture, for instance the reverb of a sheet of metal being eliminated through dampening achieved by a blanket laid underneath.
A lot of the recording process of Mirror’s Edge included designers scraping their shoes across different surfaces, hands handling objects in different ways and a lot of Stepping and jumping.
For most surfaces in the game, the designers had to create footstep and hand step sounds, together with soft, medium and hard landings. The recording process was quite strenuous for the footsteps, as not only one but several footstep and liftoff sounds have to be recorded in order for them to sound natural in game when played in a random pattern!
For gorey bone crunching sounds a sound designer would often use frozen vegetables often in combination with more slimey or jelly like substances for the fleshier sounds needed.
In terms of hardware and software, a lot of processing happened with most sound files using various filters in software. For microphones both a TLM 103 and a DPA 4011 were used. Discussion and experimentation also happened all the time, specifically regarding how certain sounds should be recorded.
Should the microphone be positioned at foot level, or should the microphone be positioned at ear height? Recording at foot level may reproduce cleaner audio, but what if those sounds sound weird as the footsteps would appear at ear’s height? Should the microphone be positioned off Axis or not? If we point the microphone right down at our feet at head level, we might simulate the sound of footsteps while tilting the head down at the feet, but the footsteps might sound off when looking ahead while running.
Another issue was that you couldn’t just run and hold a field recorder to record the footsteps. Holding a microphone introduces sounds originating from handling and operating the recorder. While this can add a lot to your run cycle in a Battlefield like experience, for Mirror’s Edge every step had to be recorded cleanly.
So the designers marked a spot on the ground and repeatedly stepped on it to get consistent and clean audio for use in the game. In the end a lot of the recording process also consists of feeling things out. If it sounds right, it’s right! And that is one of the more magical aspects of Foley recording. Making something sound as it should sound, doesn’t always have to be achieved by recording that specific thing. This is best showcased with an audio example.
[“rain” sounds]
What you might perceive as the sound of rain, actually is frying bacon. If we see a visual cue and hear a sound that is accurate enough, our mind fills in the rest! So in the end the sound doesn’t necessarily have to be spot on perfect. Sound designers may cheat all the time and get away with it, because if done right, you won’t spot the difference!
While we got pretty much every subject covered so far, we need to take a look at one of the most memorable aspects of Mirror’s Edges sound design, which would be the music!
Music #
Mirror’s Edge would not have been the same without the stunning compositions of Magnus Birgersson, or as he is best known as, Solar Fields. Mirror’s Edge almost feels like a game that was made and can only work with the Solar Fields sound and as it turns out this is no coincidence!
[Interview Excerpt with Birgersson]
Birgersson: “For the Mirror’s Edge project I was really lucky because they wanted to have the Solar Fields Sound”
Massi:”Ah!”
Birgersson: “Ja! They wanted Solar Fields for the music! So that was quite easy for me you know, but of course you had limitations to work around, everything needs to work but uhh… but uhh… Basically it was like producing music for my normal albums you know, but slightly different of course!”
After chatting with Magnus he offered to connect me to the audio director of the project, who funnily enough also is named Magnus! In my conversation with Magnus Walterstad I found out many interesting bits of information revolving around the sound design of the project which was discussed in this production earlier, but I also heard the story of how Solar Fields was brought onto the project!
Walterstad grew up listening to many kinds of music, but he was especially infatuated with synthetic ambient music. (showcase Tangerine Dream and Vangelis photos or albums)
When he was working on a concept video for the project, he was listening to Pandora, a music streaming service of the time. Pandora could recommend music based on what musicians and music genres the user liked. The algorithm then recommended a music project called HUVA Network and a track titled “Cocoon Moon” which was a piece by Solar Fields. Walterstad researched HUVA Network and found that the project was composed of a French musician and a Swedish artist, who coincidentally even shared his first name.
Walterstad thought that this kind of music would be perfect for Mirror’s Edge, and the thought of working with a Swedish musician excited him, so he began phoning every person named “Magnus Birgersson” he could find. After only two or three phone calls, he finally found Solar Fields!
Walterstad offered to bring Solar Fields onto the project and soon after Walterstad sent concept material to see what Birgersson could come up with. The music he got back was almost spot on and he described that for the majority of the project very little direction was needed for the music.
To quote Walterstad in regards to his work with Birgersson, he said this: “When you don’t have to direct someone, that’s when you know instantly the result is gonna be awesome! ”
Walterstad: “I grew up listening to a lot of different kinds of music but I had a thing for synthetic ambient music so Tangerine Dream, Vangelis, those guys. So when I was working on a concept video [for that version of what became Mirror’s Edge] I was listening to Pandora which was a streaming service back then. You could type in “I like these types of artists” and Pandora would then with the algorithm bring in pieces that would fit your taste. And there was this song that popped up, “cocoon something” by HUVA networks and like this is awesome! If I would write the music for the game this is what it would like it to sound like! So I started researching who HUVA Networks were, and it was a German guy I think and a Swedish guy. And that made me really happy, Swedes go on! I wanna work with swedes! And they have the same name as me, Magnus. So I started calling people that had the name Magnus Birgersson and the second or third person I got in contact with was him. So I said “Would you be interested in working together?” and I said of course and I said “would you be OK if I sent you the concepts? Just to see what you hear when you see the concepts” and we did. I sent him the concepts and the things I got back were like, almost spot on. When you don’t have to direct someone you know instantly when the result is awesome! ”
So Solar Fields just conducted his work as he would for an album! The music was recorded off hardware synthesizers and it was composed in Stems. Stems are different components of any given music track. For instance percussion, noise and bass could be three separate stems which could be mixed however the musician wanted them to. Birgersson only had to keep a few guidelines in mind, for instance reverb shouldn’t be present in the stems if the level isn’t taking place in a large open space, like the cavernous Storm Drains. Interestingly enough, Birgersson didn’t even play the game while composing the music for it!
[Interview Excerpt with Birgersson about using video playback for composition]
Birgersson: “I didn’t play the game during the working period at all. I had like the screen captures and sometimes of course I was up in Stockholm in the studio and I had a meeting with the level designers and then I could play through the game, but when I was in the studio I had no access to the game.”
[Showcasing gameplay segments with the music audio]
Birgersson:”I mean I had playthrough videos, so I could actually see and look on how each level was working. But the whole game… nothing was finished when I started to work with it you know, it was constant development and that’s why I also had meetings with the level designers and everything so I had their input also on what they were hearing in the level.”
What helped the designers in implementing Solar Fields music, was preplanning and stingers! The designers had an idea of how long each segment would take the player to complete and where exactly a music track would change to another, but since music isn’t mixed dynamically in Mirror’s Edge, DICE had to settle for stereo music tracks which play when triggering events in the level.
Here for instance the music resumes when Faith barges through this Red Door.
[Demo: I dont know the level, I think it was Heat not sure]
Or here we change from chase music to a calmer theme.
[Demo: Jacknife, Beginning, when you turn the Valve and jump on the pipes]
Many times tracks do not transition well into each other when crossfaded, so the sound designers employed Stingers and reverse Stingers to hide dissonant transitions. Stingers could also be used to end a music track perfectly at the end of a level.
[Demo: One of the dozens of examples for hiding bad transitions ?—> the end of a level where Faith crashes through a glass pane]
The music wasn’t always implemented in this way. While the music we got in the final product is absolutely excellent when experienced both in and outside of the game, it wasn’t truly dynamic. Remember the stems we talked about before? Initially the game mixed the stems dynamically depending on what was happening in the game. This was another aspect of the Runners Bubble; Dynamic music which responds to the players actions! So depending on if Faith idles, accelerates, fights or runs at full speed, the soundtrack would be different. This again is best showcased in an audiovisual example.
Welcome to the Atrium, one of the most beautiful climbing segments in the entire game, right in the penultimate level named “Kate”! This is a video composite, all music you hear was edited in a video editor to demonstrate how music could have sounded like if the dynamic mixing was implemented into the game.
[Audio Demo With inserted comments from time to time]
Faith will accelerate into a full sprint. Take notice of the noise and percussive layers fading in respectively.
Faith contemplates where to go next. Since she lost momentum, the percussive elements of the music faded away.
When the player consistently manages to keep in motion uninterrupted, they are rewarded with the full range the music track has to offer.
Faith jumps into the air vent and slows down. A perfect moment for a breather and again, the percussive elements in the soundtrack disappear first.
[Post Demo] I hope you don’t resent me for uncovering this secret! This demonstration, and another taking place in the Storm Drains are available in the post credits sections of this production without commentary. You might feel a bit disappointed knowing that this awesome dynamic music system was omitted from the final game. To our and the designers disappointment, technology at the time made it impossible to implement a dynamic stem based music system into the game. To explore why, we need to get into some more boring territories.
Memory Budgeting and the Playstation 3 #
This is the Playstation 3! It is my absolute favourite console of all time! But it also has many drawbacks, not so much for most consumers, but most importantly for developers who try to create new innovative systems for games. While Mirror’s Edge was a multiplatform title, it needed to be optimised for the lowest common denominator for hardware which at the time was the Playstation 3. While GPUs and CPUs were important to consider, what killed Mirror’s Edge’s dynamic stem mixing feature was the limited random access memory at the time which is why I will solely focus on that in this chapter. Let us compare some numbers!
PC’s from 2005 to 2009 generally possessed up to 4GB of RAM. Not much by today’s standards, but 4GB are enough to run any game of the time and would have easily allowed the Stem mixing feature to function while also having enough memory available to load in all other necessary assets at runtime.
The XBOX 360 only features a quarter of a PCs RAM, 512 MB. From a PC gamers perspective half a GB is very little, but a console has less going on in general when compared to a computer, which is used for games but also productivity and utility software which may run in the background while a game is running. It is little, but it isn’t too complicated to handle the RAM budget on that console.
The Playstation 3 features only 248MB of RAM. Half of the XBOX 360s RAM and an 8th of a typical PC’s RAM at the time. Everything from textures, 3D models, sound effects and also the music had to get crammed into 248MB at any given time. This of course meant that assets needed to be streamed, loaded and unloaded constantly. Audio takes up little space in RAM, the vast majority of space is boggled up by visual assets. Every Byte was worth gold, so what often happened during development was that the sound designers would sneakily implement longer audio files to reserve space in order to ensure that enough RAM would be free for anything they planned to do in the future of the project. That space of course was also freed up when more Bytes were needed to get something else to work. For a console that already doesn’t have much RAM to spare, implementing a soundtrack that requires up to 6 files or potentially more to be loaded at all times was too much to ask at the time. Sadly the stems had to go, but luckily the great music stayed!
Conclusion #
Mirror’s Edge never was a game that was meant to be. It wasn’t a game that was written down in a notebook somewhere to be found in one of the designers drawers and many of the decisions made for the game arose from circumstance. For example, the game got its iconic look one day when the developers needed to load up the game without textures to debug a problem, only to find out that the game looked beautiful without them. The concept of the game was synthesised out of many tried game concepts which for one reason or another were redone or scrapped entirely, it could maybe be considered a “happy accident”.
The game wasn’t destined to feature Solar Fields music from the beginning of the project, Birgersson just happened to have a dedicated fan on Pandora who just happened to be an audio director working at DICE, and that guy -like Birgersson- was called Magnus too!
Something that was no coincidence, however, was that the people behind Mirror’s Edge were highly skilled, motivated and harboured a mutual understanding on what their project was supposed to be about.
That understanding spawned a game that had an artstyle like no other, a playstyle that was alien to the gaming scene at the time, one of the most interesting and instantly recognizable protagonists ever designed and of course a soundtrack that is just as striking as the many locales the player may find themselves in. Hopefully this production cleared up some questions you may have had about Mirror’s Edge, or maybe you were able to come to appreciate the work of the many sound designers that made Mirror’s Edge sound great.
Many thanks to Ben Minto, Magnus Birgersson and Magnus Walterstad for your support! All music you hear in this video came from Mirror’s Edge. The Stems for the demonstration have been provided by an ex developer and the information presented in this video has been proofread by people who worked on the sounds for Mirror’s Edge.
Video of Trees in the rain from @G Korb https://www.youtube.com/watch?v=TatD16J7f2I Many thanks to the Mirror’s Edge Modding Discord! Join their Discord!
Many thanks to… Magnus Walterstad David Möllerstedt Ben Minto Mari Saastamoinen Minto Malin Arwidsson Markus Lignell Kim Creutzer Tomas Danko Rik Elliot Ulf Olausson David Silverin Magnus Birgersson …for making Mirror’s Edge sound great!!!
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