Spatial Sound for Computer Games and Virtual Reality - Game Sound Technology and Player Interaction: Concepts and Developments - page 292

Figure 4. a) The human pinna structure, b) a sound impinging and interacting with the pinna

sOUND PrOPAGAtION IN rEAL
sPAcE

acoustics are very different from the typical air-
based medium. Not only does the shape, size,
and context of the space influence acoustics, but
so too do static and moving objects within that
space as well as materials of large surfaces such
as tiled walls.

Synthetic environments in VR and computer
games are very varied and sometimes very com-
plex. Visual simulation of real-world scenes has
come a long way in terms of player immersion and
photo-realism. The more complex and detailed the
visual representations become, the more elaborate
and intricate the sonic attributes need to be in order
to match user expectations. This can pose many
problems for sound designers in terms of realistic
acoustic simulation and sound source emission.
Again, as with the theoretical understanding of
psychoacoustics, environmental/room acoustics
are well understood but the problem of imple-
menting the theory in VR and computer games
lies mainly with resource allocation and hardware
constraints.
The propagation of sound can vary dramati-
cally from scene to scene or from level to level
during an instance of gameplay. The player can be
within a small room enclosure in one scene and
change suddenly to a wide, open space in another.
Some scenes take place in unusual environments,
such as under water or in outer-space, where the

Indoor Acoustics

In the most basic terms, sound in an empty room
is both absorbed by and reflected off surfaces.
The energy that is reradiated is dispersed around
the room and the listener hears both direct and
reflected sound as a result. Between each oppos-
ing wall, a standing frequency and its associated
multiples resonate . The standing waves that are
produced express the room's resonant character-
istic: there are multiple resonant frequencies in
any one room. The acoustic result for the listener
is a reinforcement of those resonant frequencies
(by way of emphasized energy) when present in
the soundscape. (Refer to Figure 5).
Another basic feature of indoor acoustics is
reflection, which is often applied broadly in VR
and computer game environments using general
delay and reverberation units. In Figure 6a, the