Investigation of Auditory Objects Caused by Directional Sound Sources in Rooms

The auditory impression of sound sources is strongly influenced by the room, which, e.g., determines the apparent source width. What is more, typical sources are not omnidirectional, which also makes their orientation a strong influence. This influence, however, has only been investigated a little, although it can even change the perceived location of the source. To provide more insight, we performed extensive listening experiments inside our anechoic laboratory that is equipped with a 24-channel loudspeaker playback to simulate both the directional source and the room. The directional source is described by two frequency-independent 3rd order directivity designs in 36 different orientations, and the room is simulated by the two-dimensional 1st and 2nd order image source method. Results of the experiment indicate that, in most cases, the auditory location can be determined by the loudest unmasked acoustic reflection path. This allows to explain the primary direction perceived with an astonishingly simple model including precedence effects.