Wave field synthesis technology

Presentation of Sound that Leaps to the Foreground

We have been doing research on wave field synthesis technique as a means of presenting 3D sound to match 3D images rendered for multiple points of view. One topic of research at STRL is 3D TV, which enables naked-eye viewing of realistic 3D images. An acoustic presentation that makes sounds appear to originate at the location of objects in a 3D display would create a realistic sense of presence never experienced before in the enjoyment of 3D images. We are working toward achieving such a sound presentation with research on wave field synthesis technique using a loudspeaker array.

In wave field synthesis, the desired sound field is calculated in advance and used to control the amplitude and delay of sound production by each loudspeaker in a loudspeaker array. In that way, the calculated sound field is synthesized in the space in front of the loudspeaker array. By reproducing the sound field so that sound appears to be coming from a position where there is no sound source, a person who is listening to the sound presentation while viewing 3D images at the same time will experience the feeling that the sound is leaping out to the space in front of them (Fig.1).

We are also working on synthesis of complex wave fields to achieve various types of sound presentation. Synthesis of the sound field generated by a moving sound source would enable presentation of not only the moving sound object but also the Doppler effect^*1 resulted from the motion of sound source. To achieve that result, we have developed a method for calculating the sound field of a moving sound source and a method for using the calculated sound field to drive a loudspeaker array to synthesize the sound field.

Future work will aim at practical application of sound field synthesis with two objectives: 1) 3D video and audio content that is more natural and 2) various types of acoustic presentation.