The sensitivity of listeners to early sound field changes in auditoriums

The sensitivity of listeners to small changes in the early sound field of auditoria has been measured. This was done using a realistic artificial simulation system of a concert ball sound field. The simulation system was designed so that standard objective parameter values were typical of those found in real halls, and within ranges known to be subjectively preferred. The following difference limens were measured: early lateral energy fraction; inter-aural cross correlation coefficient; clarity index and centre time. From these results it was shown that when changes are made to the early sound field, changes in perceived spatial impression will usually be larger than those for clarity. Furthermore it was found that acousticians can gain most by paying attention to lateral sound. Other measurements showed that: (i) the initial time delay gap is not significant to listener preference, and (ii) diffuse reflections in the early sound field are not perceived differently from specular reflections