THE SOUND OF SILENCE
Eric Brosius reveals the secrets behind Thief ’s audio design.
Sound plays a crucial role in Thief ’s design. Players must be wary of how much noise they make as they walk across different surfaces, and must listen to the footsteps of guards to figure out when to slip by. Its bespoke audio engine propagates sound realistically, to the point where players can press against doors to eavesdrop on conversations. But Thief ’s audio design goes way beyond what is mechanically necessary. Atmospherically it is one of the strangest and most distinctive games ever made. Its hypnotic, haunting soundtrack becomes the main contributor to immersing the player in Thief ’s world, and is one of the key elements that has preserved Thief ’s playability through the years.
Thief ’s audio design was led by Eric Brosius, whose other credits include the 1995 shooter Descent, and the Guitar Hero series. “From the beginning we knew that sound had to be really important, and we had to make it clear that what you were hearing was hearable by other people,” Brosius says. “Some of that was inspired by those submarine games you used to play in the arcade where you can’t see anything but you can hear them.”
Brosius knew sound was also vital in creating the right mood and keeping the player interested. Thief was a much slower game than its contemporaries, with the majority of first-person games being high-octane shooters. As such, it needed a soundscape that made its world feel alive even when the player was doing very little. “We wanted to not have a traditional score, like a traditional cinematic-style score. We wanted to make things that helped with the immersion, creating the mood and everything. We sort of blur that line between ambient sound and music.”
Brosius prioritized embedding sound in the world to emphasize that the player was moving through a 3D space, while the ambient soundtrack comprises low drones and buzzes that are looped over and
it is one of the strangest and most distinctive games ever made
over. “My goal was to get you hypnotized into not even hearing it anymore,” he says. This also worked from a practical hardware side. “Memory was short and everything was held in memory, there wasn’t really any streaming. So everything was short loops.”
These ambient loops and 3D sounds were often designed to fit the theme of the level in question. But Brosius would deliberately mess around with their composition so that, while vaguely recognisable, they also sounded eerie, so that the player would never feel too comfortable. In Song of the Caverns, for example, Brosius used a modulated recording of an orchestra tuning up.
“I put a lot of kind of musical snippets on these emitters, so as you walk around a corner you’d hear a piece of looping music come in. And then it would kind of go away and it might mix with another one,” he says. “You got this random soundtrack that I thought fit the level because it just seemed like you were in the opera house and there was music seeping out of the walls.”
The soundtrack and effects weren’t the only important component of Thief ’s sound design. One of its best features is the dialogue, particularly between its guards. Originally, the plan was to cast British actors, but Looking Glass found that American actors fit more naturally into the game’s Raymond Chandler-inspired city.
“I remember one guy who had to come in, and we wanted to do a more cockney-style accent,” Brosius recalls. “He was quite good. But he would go,
BELOW: Sound in Thief propagates realistically. Close those doors, and the sound behind them will be muffled.
RIGHT: In The Sword, the modulated sound of Terri Brosius’ laughter eminates from the walls.