Wow they went as far as multiple layers of glass with argon pumped between them!
I'm not sure how much this carries through to sound transmission and I couldn't find a lot of good literature about it. I'd have loved to see if they did any quantitive testing. It makes sense that Argon would reduce sound transmission some, but I would expect that the properties of the glass sheet itself and the interface between the panes and the frame would be more of an issue than the void between the panes.