I live in a relatively small and very old house and have been feeling fustrated because my HT setup is confined into a 13x9' room. So I am thinking on moving everything to the ATTIC I am in the process of finishing. The Attic height goes from about 8ft down to 4 ft in the knee walls. The Attic room is 13 x 17, which I believe will help to extract better performance from my sound system. The end wall could work great to place a new plasma or a screen for a projector. Another plus, no much family traffic in the attic
Question: Will the inclined ("cathedral") ceiling create a sound problem? What is the best way to avoid deep bass sound from traveling all over the house?
No, it will not create a sound "problem" but it will affect the nature and quality of the sound. Best way to keep deep bass sound from traveling all over the house is not to use a subwoofer or speakers with deep bass capability. You did ask about the best way.