Handbook for Sound Engineers

Acoustical Modeling and Auralization 231

9.3 Auralization

Auralization is the process of rendering audible,

by physical or mathematical modeling, the

sound field of a source in a space, in such a way

as to simulate the binaural listening experience

at a given position in the modeled space.^22

Auralization systems have been in existence since

the 1950s.^23 During the early experiments, researchers

used a physical 1:10 scale model in which a tape

containing speech and music samples was played back

at scaled-up speed through a scaled omnidirectional

source while also taking into account the air absorption

and scaling the reverberation time of the model. A

recording of the sound was made at the desired receiver

locations using a scaled dummy head and the results

were played back at a scaled-down speed under

anechoic conditions using two speakers. The sound of

the model was then subjectively assessed and compared

to that perceived in the real room.

The technique—or variants of it—was used for the

prediction of the acoustics of both large and small

rooms throughout the 1970s, however, with computer

systems becoming increasingly faster and more afford-

able auralization techniques based on computational

models have been developed to yield an audible repre-

Figure 9-20. A noise map from an outdoor propagation model. CadnaA by DataKustik GmbH.

Traffic noise map

using Average

Daily Volumes/day

Noise map at 10 m

(All levels in dB-A)

Figure 9-21. Difference maps for noise generated by
different types of road pavements. Courtesy SoundPLAN,
by SoundPLAN LLC.

Difference Map

Weekday