When a sound field is sampled by a finite number of microphones, the upper- frequency range of the recorded content is affected by spatial aliasing. The frequency above which aliasing-induced artifacts occur is related to the number of microphones that constitute the array, along with the array radius and the sampling scheme according to which the microphones are positioned. In this study, ambisonics signals of order N=7 are encoded from simulated recordings made by virtual spherical microphone arrays of varying characteristics (radius, sampling scheme, number of microphones...). These aliased stimuli are then compared to unaliased stimuli of order N=7. An adaptive procedure reveals the minimum number of microphones required for aliased stimuli to become indistinguishable from unaliased stimuli.