We finished building the riser last night. It was actually more difficult than we thought it would be.
In order to get both rows of the seating to recline we made the riser about 7 feet. When you enter the room there will be a step up and then a step down to get to the first row of seating.
Mark did a fantastic job of calculating the amount of 
supplies. We only had a small amount of wood leftover.
We started out by building the frame except for the front board. We then pushed the whole thing back against the wall. After that we put on the front board. The reason we did it this way was so that we could angle the outside boards away from the side walls to refrain from putting scratches in the wall. 
Mark then drilled all of the holes in the front and installed the insulation. The reason we put insulation in the floor of the riser was so that some of the bass would be absorbed. That is also the reason we put the holes in the front. The sound will be able to go through the carpet but will then be absorbed in the insulation so that it won't be heard throughout the rest of the house.
The final step was to put the plywood on. This actually became quite the task. We had to notch out where it was around the door as well as in one of the corners. We used the router to make the edges cu
rved since we weren't able to do a full bullnose (I think that is what Mark called it).
As of right now there is no creaking and I don't think there will be because we made sure that the boards fit perfectly without being too close. We figured out that the creaking comes from the boards rubbing against each other and not from them coming loose from the framing.
To see the riser pictures CLICK HERE.