wfmag.cc \ 35Game audio part 1: Voices and listenersToolbox
Čounǁ ǁesigners perioǁicƃȢȢʰ
ǁrƃg ƃ ƹƃg oǹ cƃsh ǁoʥn to
the scrƃp ʰƃrǁ in return ǹor
diegetic sounds – other than those on top of crunchʰ neʥ impƃct sƃmpȢesӝ
the listener – play a bit faster and at a higher
pitch when approaching us, and deeper and
slower as they recede.
The same principle, on a grander scale,
affects the colours of stars in the night sky.
Those approaching Earth are shifted to
the bluer, higher frequency end of the
optical spectrum, while
the majority are moving
away, causing the so-
called redshift.
If we represent sound
radiating from a source as
concentric ripples, these will be evenly
spaced around a stationary source. In Figure 4,
listeners on either side of the first source hear
it at the same pitch. But the second source
is moving, so the waves it emits are packed
together in front and spaced out behind.
The pitch heard depends on which
side the listener is.
The ‘correct’ formula depends in principle on
the speed of sound and, in practice, also the
scale of the game. A few sounds like church
bells sound weird if given the ‘correct’ amount
of 'oppler and need to be scaled down, as
we did in Colin McRae Rally, to sound realistic.
Even when placed in the world, music sources
from static radios or PAs sound weird if
'oppler-shifted around a fast-moving listener.
5emember, it’s a game – prioritise the most
significant sounds and tweak them continuously
so the player doesn’t factor them out and can
infer useful things from the fluctuations.
Figure 5 shows how sounds are grouped and
mixed in racing games, like my F1, Lego Racers,
DiRT Rally, and Race Driver titles. 2ther ' sims,
including shooters, sports games, and even
physics-based puzzles, use similar categories.
Notice how music and
speech are grouped
separately. These non-
diegetic sounds might
have their own volume
controls, in the pause
menu. Game music may be overridden by the
user’s own – 0icrosoft’s ;03 feature reTuires
this, and it’s easily done on PlayStation and
iOS too, though not compulsory. Speech could
be routed directly to the player’s headset, as
shown, or mixed into the main speakers.
Apart from menu beeps and notifications, in
the Ȇ)ront end+8'’ group, all the other sounds
are positioned in ', relative to two virtual
microphones or ‘listeners’ placed in the game
world. Player-centric sounds have their own
listener, and equivalents from other players or
AI cars are mixed with environmental sounds –
local ambience, crowds, and weather – into the
View Listener.
In the second part of this article, we’ll
consider how sounds are placed and processed
so that each gamer gets a custom mix.SOUND JOBS
Audio team roles split beyond
designers, composers, and
programmers to include
game trigger, effect, and
mixing system programmers,
nlus fullżtime snecialist
designers concentrating on
dialogue, location recordings,
frontżend, ambience, and
engine noises. Codemasters
has specialists who do
nothing but capture engine
recordings on location
(unless you’re Phil Spector,
it’s frowned on to re{ motors
in the studioŹ or ha{e a fullż
time job editing the results,
back at the officeŬ“Modern games
can mix a hundred
or more voices”Game audio part 1: Voices and listenersToolbox
Figure 5: Čourcesӗ miʯ-groupsӗ Ȣistenersӗ ƃnǁ outputs soon
ƃǁǁ up ʥhen simuȢƃting the sounǁ oǹ ƃ motor rƃceӝMain
Speaker
OutputsPlayer’s
headset or
controller
User music
XMP overrideCommentary Pit radio
Network chatFront-end musicLoading loop
Replay musicPosition changeNew lap record
Select/Cancel etc.
Wind and rainCrowds
EnvironmentsWipers, Horns Displacement
Sense of speedCrashes, ScrapesProp collisions
Breaking glassRolls, Splashes Peels, Scrubs
Bumps, Skids
Engine Exhaust Aspiration
Transmission DamageSpeechMusicFront-end and HUDEnvironment ambienceMisc vehicle soundsCollisionsPlayerWheels and surfacesCollisionsPlayerAI CollisionsAI WheelsAI EnginesView
ListenerPlayer
Listener