Room acoustic prediction and auralization based on an extended image source model

Abstract

During the 1980s, an exciting new technique was developed that put great demands on prediction methods. This new technique, called ‘‘auralization’’ in an analogy to visualization, enables the designer of a concert hall to get an aural impression of the hall before it has been built. By the calculation of highly detailed octave-band echograms, the use of signal-processing techniques and measured head-related transfer functions, a binaural room impulse response can be synthesized. This response is convolved with anechoically recorded music to give an impression of how the music would sound in the completed hall. This paper describes auralization using the image source model. This model, as well as others, has its share of short comings. In an attempt to compensate for some of these, the basic model has been extended. The two most important extensions are the treatment of scattering and the use of ray tracing to estimate the late part of the echogram. The combined method enables reasonably fast calculations, highly detailed early parts of the echograms, and smooth transitions to the late parts. The predicted measures compare well with measurements and the aural impressions created sound natural.