Redesigned Window Stops Sound But Not Air (opens in new tab)

It's not terrible, it's certainly impressive that they achieved that level of isolation with holes in it. Windows designed for high sound isolation will have STC ratings in the 40-48ish range. An STC increase of 10 equates to half as much sound passing through (as a human perceives it anyway).

As for the air passage, I'm curious about the real world flow numbers.

Just an off the cuff guess: it seems like the core principle is based on resonant cavities which I think would result in higher air pressure in the cavity than inside or outside the window. In a setup like that with calm ambient conditions I wouldn't think much air would actually pass through the panels, the higher pressure in the cavity would act as a bit of a wall. In windy conditions I would imagine much more air would pass through, but I bet there would be a corresponding decrease in sound isolation as air blasting through the cavity wouldn't be able to dissipate as much energy.

I live in the countryside. Ask me about neighbouring Sheep, Goats, barking Dogs, braying Donkeys, logging trucks, tractors, screeching Baboons, honking wild Geese,...

I don't think you are. I came across this a number of months ago and looked into building one myself. You could pretty easily start out with a couple of sheets of acrylic and make a grid to separate them. Then you just have to drill a lot of holes. I think getting the grid right would be the hardest part as a DIY project, but you could pretty easily imagine a machine cutting slots so it all fits together nicely.