Coincident Arrays vs. Spaced Arrays

The Coincident techniques (localisation cues based only on level differences between signals) can create proper localisation accuracy, but will lack envelopment and have a small sweet spot (in two dimensions - left/right and front/rear!) The advantage of a coincident array is, that it is compact and portable.

A Spaced microphone surround array will create a three-dimensional enveloping sensation by providing adequate amount of decorrelation between the signals (localisation cues are based on time-of-arrival differences). When adapting the microphone placement (distance and angle) to the sound field, spaced arrays still provide proper localisation accuracy.

The Spaced techniques in general give a nice and large sweet area and you sense the enlarged and enveloping sound stage in a larger listening field. The disadvantage is the size and in some situations set-up time.