Amplitude-decorrelation avoiding spectral artifacts of sound field synthesis in the anechoic chamber or free sound field

Sounds to appear in directions between the loudspeakers will typically activate neighboring loudspeakers with the same signal when spatially rendered. The resulting interference causes frequency- and position-dependent cancellation in the superimposed sound field. While keeping the number of active loudspeakers uniformly small is often enough to have the few acoustic reflections of a studio environment conceal the unwanted cancellations, they will remain a problem when synthesizing sound fields in the anechoic chamber or free field. Our contribution investigates short filters for amplitude decorrelation to reduce this problem. The filters supply neighboring loudspeakers via frequency responses that are mutually exclusive and hereby avoid cancellation in the superimposed soundfield. This only works at the expense of requiring a minimum spread to ensure a spectrally balanced synthesis, i.e., by avoiding to activate single filtered loudspeaker, alone. We present a listening experiment investigating in how far the proposed filter strategy is able to improve the spectral stability within a reasonable range of motion for a seated listener, in the anechoic chamber. Other thinkable approaches are investigated for comparison.