In reply to:
Question for you -- on the drawing, it looks like the "D" area is the left hand side of the top part of the floor, with the right hand side being "something else". Is that correct, ie will the room's long axis run "up and down" ? Are you going to drywall all around the room or will there be openings ?
That right hand wall will be drywalled indeed. The room itself will be a rectangle except for a small nook that starts underneath the lower venting on that right hand wall which the a/v equipment will be put into. The tv/screen will go against the very top wall while the couches will be more towards the bottom.
I'll add another scan later of a newly sketched design that incorporates some doors and walls although not quite to scale.
As for the second part, weakness in that low bass range can be compensated with several methods: second subwoofer, louder volume gain on present subwoofer or relocation of the sub closer to a corner.
Personally i like the second subwoofer idea.
This system will become primarily HT but any entertaining in the games and wine cellar will be fed by the equipment. I haven't decided yet if i'm going to use zone 2 or whether the distance from this system into the games room will suffice. With 2 french doors opening into the media room, the bottom wall will not be very closed off unless the doors are shut.
