I just completed my HT room. After using resilient channels with 1/2" drywall to isolate the sound from the rest of the house I find the room too "hot" acoustically. I mean when I clap my hands I get a ringing echo. In professional rooms when you clap your hands the sound just disappears-no echo. I can't afford those acoustic wall systems, are there any simple treatments to dull down the room? Tapestries, curtain panels etc? Does anybody understand what I am trying to explain? My wife doesn't. Sonically everything sounds too bright.