This is one of the few disappointments / compromises I've had so far with this house. This room is supposed to be a home theater some day. Despite meetings with the builder and plumber, they were unable to find a different location for this drain line. Therefore, I'm going to have to drop the ceiling height in a room where I wanted maximum volume. As it is, it wouldn't be too bad. However, I planned to install a riser to raise the floor in the rear of the room to elevate the back row of seats. By doing this and dropping the ceiling to accomodate the drain line, ceiling height in the rear will only be about 7.5 ft.
This could have been avoided by (a) pouring an 11 ft concrete wall or (b) digging out floor an additional foot in the front of the room before the footings were poured.