Auralization is a procedure designed to model and simulate the experience of acoustic phenomena rendered as a soundfield in a virtualized space. This is useful in configuring the

soundscape A soundscape is the acoustic environment as perceived by humans, in context. The term was originally coined by Michael Southworth, and popularised by R. Murray Schafer. There is a varied history of the use of soundscape depending on discipline, r ...

of architectural structures, concert venues, and public spaces, as well as in making coherent sound environments within virtual immersion systems.

History

The English term auralization was used for the first time by Kleiner et al. in an article in the journal of the

AES AES may refer to: Businesses and organizations Companies * AES Corporation, an American electricity company * AES Data, former owner of Daisy Systems Holland * AES Eletropaulo, a former Brazilian electricity company * AES Andes, formerly AES Gener ...

en 1991. The increase of computational power allowed the development of the first acoustic simulation software towards the end of the 1960s.M. Vorländer. ''Auralization : Fundamentals of Acoustics, Modelling, Simulation, Algorithms and Acoustic Virtual Reality''

Principles

Auralizations are experienced through systems rendering virtual acoustic models made by convolving or mixing acoustic events recorded 'dry' (or in an

anechoic An anechoic chamber (''an-echoic'' meaning "non-reflective") is a room designed to stop reflections of either sound or electromagnetic waves. They are also often isolated from energy entering from their surroundings. This combination means t ...

chamber) projected within a virtual model of an acoustic space, the characteristics of which are determined by means of sampling its

impulse response In signal processing and control theory, the impulse response, or impulse response function (IRF), of a dynamic system is its output when presented with a brief input signal, called an impulse (). More generally, an impulse response is the reac ...

(IR). Once this

h(t)

has been determined, the simulation of the resulting soundfield

s(t)

in the target environment is obtained by

convolution In mathematics (in particular, functional analysis), convolution is a mathematical operation on two functions ( and ) that produces a third function (f*g) that expresses how the shape of one is modified by the other. The term ''convolution' ...

r(t) = h(t) * s(t)

The resulting sound

r(t)

is heard as it would if emitted in that acoustic space.

Binaurality

For auralizations to be perceived as realistic, it is critical to emulate the human hearing in terms of position and orientation of the listener's head with respect to the sources of sound. For IR data to be convolved convincingly, the acoustic events are captured using a dummy head where two microphones are positioned on each side of the head to record an emulation of sound arriving at the locations of human ears, or using an

ambisonics Ambisonics is a ''full-sphere'' surround sound format: in addition to the horizontal plane, it covers sound sources above and below the listener. Unlike some other multichannel surround formats, its transmission channels do not carry speaker si ...

microphone array and mixed down for binaurality.

Head-related transfer function A head-related transfer function (HRTF), also known as anatomical transfer function (ATF), is a response that characterizes how an ear receives a sound from a point in space. As sound strikes the listener, the size and shape of the head, ears, e ...

s (HRTF) datasets can be used to simplify the process insofar as a monaural IR can be measured or simulated, then audio content is convolved with its target acoustic space. In rendering the experience, the transfer function corresponding to the orientation of the head is applied to simulate the corresponding spatial emanation of sound.

Notes and references

Application software Acoustics

History

Principles

Binaurality

See also

Notes and references