Researchers have employed numerous array configurations and sampling densities for measuring sound radiations of live sources, including musical instruments and the human voice, with the sampling positions varying from well under a hundred to far more than a thousand. These inconsistencies highlight an underlying knowledge gap regarding the required numbers and positions of sampling positions for ideal directivity measurements. This work presents theoretical methods and practical metrics to clarify how to mitigate spatial aliasing effects for a given source. Initial results of theoretical and numerical models generalize to live source measurements. Further developments explore how source placements, acoustic source centering, and diffraction about the human body impact necessary sampling densities.