[radiowave]

At a rough guess from the audio samples, that array is producing an acceptance angle much narrower than any Soundfield mic is capable of. The noise source is only 45 degrees off-axis; I'd say any first-order microphone polar pattern (i.e. those a Soundfield mic is capable of) would capture more of the noise than is demonstrated here.

Of course, you can improve on the rejection of off-axis sound by instead using a microphone with a more specialized polar patten (e.g. a shotgun mic), but then you lose the property of the pattern being steerable merely by signal processing.

Lastly, such an array of dirt cheap pressure sensitive mic capsules with some clever computation behind them strikes me as the sort of thing you could throw Moore's law at, if you could justify the quantity. Whereas, Soundfield mics don't make much sense unless you're working with very precisely machined pressure-gradient capsules.

Still, I get the feeling it'll be a while yet before this technique starts looking viable for audio production work, but it's very interesting.