KHG

I am designing a new house and have a question regarding placement of my Forte IV's used for stereo music. One speaker is in a corner with an interior 1/2" drywall over 2x4's and a 2x6" exterior wall with 1/2" drywall. The other has a double paned glass window wall behind it. My thought was to place rockwool insulation in the corner walls. The glass wall has me stumped. Any suggestions? Thanks.