Looking at the photo of the store, the top halves of the two side walls seem to be flat and empty. Maybe they could put some nice-looking sound-absorbing materials on those walls?
Perhaps they have some leftover material now that the iPod socks are EOL :)
http://appleinsider.com/articles/12/09/26/apple-removes-ipod...
Looking at the photo of the store, the top halves of the two side walls seem to be flat and empty. Maybe they could put some nice-looking sound-absorbing materials on those walls?