Image Fusion, Broadening, and Displacement in Sound Location
Mark B. Gardner · The Journal of the Acoustical Society of America · 1969
The fusion or blending of two or more spatially separated complex signals (such as speech or music) into an apparent single image requires that the common origin signals be alike in quality and follow each other in rather close sequence (within about 50 msec). If both the quality and arrival-time conditions are fully met, complete fusion appears to occur and a single image is heard coming from a single location. If these conditions are only partially met, then only partial fusion or image broadening results. The degree of broadening may be relatively small, or it may be sufficient for the image to appear to fill the intervening space between the physical boundaries of the real sources. For certain combinations of parameters, the creation of a single image either inside or outside these boundaries (image displacement) may occur. The present paper describes a number of arrangements that may be used to achieve each of these effects. The techniques employed date from as early as the mid-nineteenth century to the modern filter and computer techniques of recent years.