I have a cathedral ceiling. It's a big no-no for stereos, because of the relection back at the stereo. A good heavy rug will help, as well as padded couches etc. for more absorbtion. I think you are confusing people by saying you prefererred the old "lively" room. Your problem with the bass is cause for more bass traps and absorbtive furniture. A "lively" room is usually achieved by more reflective surfaces, giving more high frequencies. In you case I think the problem is too little absorbtion, causing standing waves that are eliminating frequencies. Certain materials, like your glass slider, are highly reflective at high frequencies but absorb low frequencies. If a big panel vibrates with the music, it is turning sound pressure into movement, so it absorbs that frequency.
A few tests: Clap your hands together HARD. You will probably hear a quick succession of diminishing echoes. That's a flutter echo, and needs absorbtion. Bass reflection can actually cause diminished bass, because if any reflection is exactly out of phase with the original, you will hear nothing.
You need expert advise. Send a detailed drawing of the room to echobusters, and they can tune the room for you. http://www.echobusters.com/page9.html
A few tests: Clap your hands together HARD. You will probably hear a quick succession of diminishing echoes. That's a flutter echo, and needs absorbtion. Bass reflection can actually cause diminished bass, because if any reflection is exactly out of phase with the original, you will hear nothing.
You need expert advise. Send a detailed drawing of the room to echobusters, and they can tune the room for you. http://www.echobusters.com/page9.html