Mixing is a very sensitive process, requiring sometimes microscopic adjustment of faders and hooking up the Mackie gear gave us this control. Juan was able to control the levels of all the sounds in the game via what was, for him, a familiar interface.
We essentially mix in-game by having ‘mixer snapshots’ called up by the game code and installed at various points in game play. For example, when Tony Montana is outside in the day time we have a mixer snapshot called ‘on_foot_day’ that we call every time this situation occurs, allowing us to set the levels of all the sounds for that moment. Every time Tony goes inside a building we call a ducking mixer which pulls down the ambience channel a little and makes it feel more like the player is inside that building.
We manage the levels, and even the pitch and amount of sound sent to the LFE, of every sound in this way. In Tony’s Rage Mode for example, we dropped the pitch of Tony’s weapon and also increased the volume (and sub!) of that weapon to give a really crazy powerful effect, which makes that mode feel very different to normal combat.
As the game is being played you can see the mixes change on the board in real-time, and whenever we wanted to adjust something we hit the ‘Record’ button, which grabs the last snapshot mix that was installed, and lets us edit it there and then in real-time. When we were done adjusting the levels we hit ‘Play’ and release the mix back into the game, where it is stored. That’s all there was to the process. It was actually one of the easier and less involved things to do in the whole game development process; the real skill was in the ear of the mixer.
The first thing we realized when we got the game on the stage is that the game was pushed incredibly loud, everything was competing for attention. Most games are pushed this way in development and are in fact only A / B compared to other games, which of course are also far too loud. Being able to compare it to a movie rather than another game at reference levels enabled us to bring everything down and that gave us the headroom to pick out one or two really important sounds that would otherwise get lost in the cacophony of our combat scenes.
The head-exploding squib sound for example is a sound that we simply couldn’t hear no matter how much we crunched the wave file, even though it was playing at full volume. We had an ‘explosions bus’ routed to stand up above everything else and so were able to send this one sound to that bus. This whole process raises interesting questions about calibrating game audio. There is currently no measure, or reference level, for games; the sounds you put into a console are certainly not the sounds you get out. Games have always had to be equal to or greater than other loud games. This introduces over-compression problems and a vast reduction in dynamic range, which are already great problems in games, without being exacerbated by games continually getting louder.
A lot of what we were doing at the mix stage also involved us going back over our cinematic scenes and putting in new sounds, remixing the music and dialogue levels and re-bouncing those into the game. All our sessions for these were run on Nuendo and for any additional sounds we passed the movie over to our sound effects editor Mac Smith, who would work on the additions in Protools and pass us back the file containing the new sounds.
I’d then be able to import those new sounds straight back into Nuendo and bounce them out as a 6 channel or Pro Logic 2 encoded file. We added a lot of sound that felt missing, from footsteps and Foley sweeteners, to door squeaks, and this made a huge difference to the quality of those final movies.
We essentially concentrated our first three days of mixing on the first three hours of game play; we wanted those first moments that the player picks up this game to be of the highest quality. After this we went through the entire game, playing through every mission and making tweaks in real-time when they were necessary.
Most of the decisions we made for those first three hours carried right through into the rest of the game. For example, all the levels of Tony’s weapons against those of his enemies are cloned any time you encounter enemies, so the daunting task of mixing a huge game like this became much easier once those early changes started to spill through the rest of the game.
After our two weeks of mixing the PS2, the difference between what we arrived with was quite amazing. You can hear every sound; dialogue, music, the chaotic bullet fly-bys and the bullet impacts on the walls behind you. The old version of the game feels much weaker and sounds much muddier. The older weapons, that we had thought felt very powerful, sound very weak by comparison to the huge sound we now found ourselves hearing.
We deliberately spent two weeks mixing our target platform the PS2 up front. We then migrated all those changes over to the Xbox version of the game for a final week of tweaking for the Dolby Digital 5.1 offered by the Xbox. The extra separation you get on the Xbox through the discreet surrounds is quite something, and the Xbox definitely deserves the time spending on it to get it sounding as good as it can from an audio point of view. It has many advantages over the Pro Logic 2 encoding of the PS2.
6) Working with THX
THX’s involvement in the project, particularly during post-production, proved to be highly valuable. The THX Games certification not only encompasses audio but also the visual environment in which the artists work. THX certification is designed to ensure game developers always work in highly standardized environments with calibrated equipment, whether that’s a PC workstation (for texture artists, etc.) or a large mixing studio, like the ones at Skywalker Sound.
The THX engineers visited Radical as we were entering our Pre Alpha stage of production and took measurements that enabled us to calibrate all the art lead’s monitors, and led to the establishment of a THX room on the game team’s floor in which any artist could drop by and check their work on calibrated equipment.
The THX Professional Applications Engineer, Andrew Poulain was on site when we set up the mix stage at Skywalker in order to ensure the room and equipment was calibrated correctly, which again proved invaluable for our mix to take place as we were making a lot of critical artistic decisions about the audio in this environment, and we had to know that what we heard was entirely accurate.