Apparent Source Width and Listener Envelopment in Relation to Source-Listener Distance

The perceptions of ASW and LEV at different source-listener distances in a reverberant soundfield were investigated
subjectively and objectively. 12 subjects graded the magnitudes of perceived ASW and LEV for trumpet and conga
sounds that were convolved with binaural room impulse responses measured at 3m, 6m and 12m from the source. Both
ASW and LEV were found to decrease significantly and almost linearly per doubling the distance. The distance-
dependent ASW was best predicted using objective measures called GE (early sound strength) while the LEV results
were highly correlated with GL (late sound strength) and B/F ratio (Back/Front energy ratio of late sound). Such
conventional measures as [1-IACCE], [1-IACCL] and LF did not agree with the perceived results. The findings of the
current study are expected to provide psychoacoustic basis for controlling virtual front-back listening positions in a
reproduced soundfield.