we are planning to insulate a solid wall by battening some mineral wool blocks, then covering with acoustic plasterboard. We will put retaining bolts between the battening and plasterboard, but i'm wondering if it's useful/possible to put them (or just long screw sections) between battens and original wall, to reduce the amount of material against the original wall and make more air gaps (though the mineral wool blocks will touch the original wall). i've read that bass sound goes through timber very well, so isolating it seems sensible, but i don't want to build a whole new stud wall. any ideas?