Driver Details

The original design posted on these pages called for a dual 15" driver in a 17 cubic ft. enclosure under the stairs running flat to 20Hz.  That perhaps sounds like it was a little bit overkill?  After further consideration my calculations also showed that it would be low and loud but would generally sound terrible in the transients department. 

The next design iteration took me to using the newly introduced Dayton Loudspeaker Titanic 1200.  The general consensus called for a 3.3 cubic ft. sealed enclosure that would produce a Qtc around .75.  I built the prototype and installed it in the cabinetry of the theater firing towards the audience.  Good news was that it was near the corner of the room, out of sight and perfect for music.  The bad news was that the output was very much lacking oomph (a very technical term) for movies.  After some deliberation the decision was made to keep the driver but scrap the original box design.

The driver now sits in a 2.3 cubic ft. sealed cube that doubles as an end table (or it will once I clean it up a little).  This implementation produces a flat response  with a 35 Hz f3 point and a much rounder sounding Qtc of .86.  The enclosure is now capable of being positioned anywhere in the room for greater flexibility, is small enough to fulfill the requirements as determined by the SAF(*), has better power handling during loud passages and produces great sound for the theater application.  I'd provide a picture but it's really nothing to look at so far unless you're into a butt joint cube of birch plywood.

The sub is being powered by a 150W sub amp from Parts Express (300-800) which has been kept separate from the sub to improve the rigidity and air-tightness of the enclosure.

* - Spouse Approval Factor (SAF)