Putting new window into existing frame with existing window
 

Hello,

It may sound confusing, but here's a brief illustration

http://i33.tinypic.com/rh7sas.jpg

the window I'll be installing has the flange around it ready to be nailed in, which I will probably do first instead of putting any caulking just in case.

The reason behind this is for soundproofing, which is why there's the optimal 2-3 inches of air space. If anyone knows anything about soundproofing windows feel free to chime in.

Will this work? (install correctly, soundproof, etc.)