The evaluation of binaural playback systems for virtual sound fields

By means of virtual acoustics technologies the impulse response in a location of a real enclosure can be used to create a virtual room. Also in this virtual space, typically implemented in a dead room, an impulse response can be measured. From both “real” and respective “virtual” impulse response a group of room-acoustical parameters can be calculated. The match of the two groups of indicators mostly depends on the layout of the playback system and on the implemented processing. In this paper a procedure of virtual measurement in a dead room is developed and some typical layouts of playback systems employing two loudspeakers are compared. Based on the consistency of the room-acoustical indicators derived from “real” and “virtual” impulse responses can be investigated. It is shown how the performance depends on the angular separation of loudspeakers and the efficiency of the cross-talk is also tested and discussed. Finally, a set-up which is suitable for psychoacoustics tests is indicated.