Full-bandwidth array directivity is practically infeasible due to aliasing cost

Evidence

Avoiding spatial aliasing requires a huge number of small loudspeakers, resulting in a prohibitive cost for the array. For example, ideally we want pattern control over the entire audio frequency range. However, even if we make the speaker spacing 4.3 cm, which is unfeasibly small because we would need a large number to achieve low-frequency pattern control, we still have significant aliasing at 10kHz. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2906