# THE RELATION BETWEEN SPATIAL IMPRESSION AND THE PRECEDENCE EFFECT **Abstract:** 1. INTRODUCTION Auditory spatial impression (ASI) is a multidimensional characteristic of human auditory sensation associated with the acoustics of a space. ASI comprises at least two perceptual components, auditory source width (ASW) and listener envelopment (LEV). Figure 1 illustrates a flowchart of human subjective evaluation of sound environment. An acoustic signal S(ω) radiated from a sound source is affected by a room transfer function R(ω) and arrives at the position of a listener. The composite acoustic signal is expressed as S(ω)xR(ω). This composite acoustic signal is then affected by head-related transfer functions Hl,r(ω) as it arrives at the entrances of the right and left Physical Space S(w) Psychological Space This paper reviews results of listening tests on auditory spatial impression (ASI) that describe the relation between individual characteristics of spatial impression and the precedence effect. ASI is a general concept defined as the spatial extent of the sound image, and is comprised at least two components. One is auditory source width (ASW), defined as the width of a sound image fused temporally and spatially with the direct (preceding) sound image; the other is listener envelopment (LEV), defined as the degree of fullness of the sound image surrounding the listener, and which excludes the direct sound image for which ASW is judged. Listeners can perceive separately these two components of ASI, and their subjective reports demonstrate that they can dis **Authors:** [[Masayuki Morimoto]]