One of the issues in creating a good audio experience in a 'sensitive; decorative environment is how to deal with the subwoofer.

Here is a simple design that can be created in decent MDF and hidden under kickboards, bath panels etc.  This design is not particularly efficient but does run clean and low and is reasonably tolerant of placement.

  You'll find the necessary calculations at:

http://www.diysubwoofers.org/bnd/4thord3.htm