Perceptual Band Allocation (PBA) for the Rendering of Vertical Image Spread with a Vertical 2D Loudspeaker Array

A series of subjective experiments were conducted to investigate a novel vertical image rendering method named “Perceptual Band Allocation (PBA),” using octave bands of pink noise with a vertical 2D reproduction setup with main and height loudspeaker pairs. The perceived height of each octave band was first measured for the main and height loudspeakers individually. Results suggested a significant difference between monophonic and stereophonic images in the perceived relationship between frequency and height. Six different test conditions have been created aiming for various degrees of vertical image spread, in such a way that each frequency band was mapped to either the main or height loudspeaker layer based on the results from the localization experiment. Multiple comparison tests were conducted to grade the perceived magnitude of vertical image spread. It was generally found that various degrees of vertical image spread could be rendered using different PBA schemes, but the perceived results did not fully match predicted results based on the localization results. Differences between the main and height loudspeaker layers in the spectral weightings of ear-input signal at certain frequencies was identified as one of the factors that influenced this result.