Thanks for the comment BBN, a bit OT and I hope NickSwampMKE won't mind too much...?
I do think that my builder pulled a fast one on me, thinking that he could build a sound proof Home Theatre type room with resilient channels. On his first try, the ceiling was not double framed and we got a professional sound guy to come in, The sound guy explained that the ceiling of course needed to be double studded, which I thought had been quite clear from my specs at the onset. Anyway, they redid the ceiling but the sound guy said that there would still be some leakage via the floor, since it is not floating.
So I think it is possible that the framing of the room touched the framing of the house in some fashion, can't fully recall now and the ceiling is built using a resilient channel (as well as all the side walls), but there is some contact with the floor joist above. The sound leakage is much more obvious just above, in my kitchen. I think the whole room gave me around 25-30 db reduction, which is till not bad, but not really helping me much at 110 db.
Thanks for chiming in BBN.
Jean.