The Perception of Vertical Image Spread by Interchannel Decorrelation

Subjective listening tests were conducted to assess the general perception of decorrelation in the vertical domain. Interchannel decorrelation was performed between a pair of loudspeakers in the median plane; one at ear level and the other elevated 30° above. The test stimuli consisted of decorrelated octave-band pink noise samples (63–8000 Hz), generated using three decorrelation techniques—each method featured three degrees of the interchannel cross-correlation coefficient (ICCC): 0.1, 0.4, and 0.7. Thirteen subjects participated in the experiment, using a pairwise comparison method to grade the sample with the greater perceived vertical image spread (VIS). Results suggest there is broadly little difference of overall VIS between decorrelation methods, and changes to vertical interchannel decorrelation appear to be better perceived in the upper-middle-frequencies.