I'm almost finished wiring my room (loft) and now I need to begin considering built in acoustical treatments. I will be able to hang surface treatments after the loft is finished so for now I'm wondering if there is anything I can do as far as 'built-in' or large installation type treatments.
The listening room dimensions are as follows:
*45 ft wide, completely open with only a kitchen island interrupting this width.
*23ft deep, with a enclosed hallway (10'highx4'widex 30'long) disrupting the open space on the back wall (see pics)
*14ft high ceiling on left side tapering to 12ft on right side.
More details:
1. I will be sitting midway down the 45 ft length so there will be about 20 ft open on my left and right side before waves hit the first refelection point. the speakers will fire across the 23' area which will actually be 18' since there is a hallway wall behind the listening position.
2. The enclosed hallway walls were built using alternating stud pattern so as not to couple the inner and outer surfaces. Drywall will be hung on sound channel to further aid acoustics behind listening area.
3. Finished surfaces will be a 50% mix of sheet rock and raw brick.
Here are some pics:
This picture shows the wall where the system will sit. The rear of the speakers to the brick wall. This wall is 45 ft long, I will look at this wall when listening.

This pic shows the hallway behind the listen area. I will be sitting near the small ladder on the wood framed wall. Above the hallway is open...a good place for permanent treatmens?

Thanks for the help you guys are giving along my journey.
-chris