After trawling through the many threads and links and professional websites I have gathered enough knowlegde and I am about to do this (well TBH I'm halfway though it!) We have an extension to an old house, with the living room downstairs and my toddlers room above. It is only a few years old and the soundproofing is a joke. There is hardly any loss of sound when you stand above the TV in my daughters room. I don't think they put any insulation in As I have the headroom, I have built another ceiling in the front room. It is 3x3 timber as the main support with 3x2 cross members. It is approx 40mm from the original (which it doesn't touch at all) and in the void I have screwed wickes high density blocks to the original ceiling. Leaving an air void of 10mm (this is where I am ATM). Next I intend to put 12mm plaster board up then get it skimmed. Now, do people think this is enough? 2 more options I can think of, another layer of plaster board and rock wool in the rafters of the new ceiling. I don't want to do these if they are overkill or serve no real purpose, but I would be devastated if after all this work and cost there is still noise in my little princess room!