Heard About: Sega Rally
Tuesday, 16th October 2007 at 10:24 am
In our monthly look at the audio production of a recently released or upcoming game, John Broomhall speaks to Sega Rally audio director Tim Bartlett on the rebirth of a classic racing franchise…
Developer: Sega Racing Studio
Audio Direction: Tim Bartlett
Sound Design: The Audio Guys
Original Music: Bob & Barn, Side UK
Approx 5500 sound files, approximately one hour of music and a small amount of pace note dialogue for speech
It’s not every day you get paid to think the unthinkable, but for Sega Rally, the audio team were invited to re-think their approach to the genre by studio director Guy Wilday.
For The Audio Guys’ Tim Bartlett, a veteran of driving games such as Colin McRae the outcome was a radical shift. He explains: “There’s little concept of engine loops in Sega Rally though we haven’t gone wholesale for synthesis. Our focus is real-time manipulation of set-piece recordings. If you use frequency analysis to compare the output of a traditional cross-faded engine loop system against real car recordings a lack of accuracy is soon apparent. It’s easy to assume that when you artificially shift the pitch of engine loops, the harmonic relationships between different elements will stay the same – but it’s not so in real life. There’s a big difference because of the complex relationship between those elements, depending on RPM and engine load.”
Whilst acknowledging how well the engine-loop approach has served driving games previously, Bartlett figured that with hugely enhanced CPU power available on next-gen consoles, it might now be feasible to manipulate sample data at run-time in ways that would previously have been dismissed. “We still use sampled assets from rolling road recording. But coding is now leading the way in controlling these sounds in real-time according to RPM and load with some serious time-stretching and synthesis akin to something like Melodyne – we are manipulating set-piece recordings of car behaviours to match the players’ driving,” says Bartlett. “It’s no technical ‘walk in the park’ and requires a serious programming investment, but I can safely say I’d never go back to a loop-based approach.”
For the raw material, around 20 cars were recorded on a dyno with four channels (engine, exhaust, gearbox, turbo) being captured at 24-bit 96kHz, a process not without its headaches. Adds Bartlett: “We had access to a rare Ford RS200E worth about £250,000. Whoever installed the brand new gearbox had made a slight oversight – no oil! As we ran it for it’s first time out that year, it went BANG, literally leaping off the rollers and doing about £15,000 worth of damage – very scary! Amazingly, when it was all fixed, they brought it back.”
Another vital area of Sega Rally’s audio is the rolling sound of wheels on track, together with the debris kicked up. Innovative design meant a more granular approach, as Bartlett explains: “We have a dynamically changing blend of two surface elements – top and bottom with the sound mix determined by how much of the top has been worn away. Each wheel can potentially be on two surfaces, so that’s four possible surface sounds for each wheel. We have two playback types – a) the constant ‘rolling’ sounds and b) the ‘kick-up’ system dealing with what’s thrown up into the wheel arches which uses a full-on granular approach. Avoiding sound library CDs, we bought ourselves a car door from the local scrapyard, put lavalier mics inside it and postioned a pair of 411s slightly further away. We recorded all manner of material being thrown at the door to collect our sound ‘granules’ which are logically played back according to car speed and the looseness of the surface. Add in the surface loops and the result is a truly coherent overall sound that makes the car feel very connected to the road.”
This combination of engine and surface sounds is further enhanced with environmental DSP – reverbs assigned to each side of the car, which change according to the environmental detail. Adds Bartlett: “To me, it’s just another tool to reinforce the ‘reality’ of what you’re seeing on-screen – the more audio tricks you can use to fool the brain into buying the overall experience, the better. Some levels have 300 different reverb pre-sets.”
Compared to some of his previous driving game productions, Sega Rally gave Bartlett the opportunity for a little creative license: “There are less reasons to stick to realism than in a more pure sim, so if we felt that boosting or distorting engine sounds would work well creatively, we went right ahead to make them sound ballsy in the game. It’s a stylised title and we’ve reflected that in the both the music direction and a generally ‘larger than life’ approach to sound – with the onus on fun!”
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