The November 2011 issues of QST magazine features a DSP speaker DIY Construction project by Allen Baker, KG4JJH.
For those that would like to "get a jump" on ordering the parts for this project. the details can be found on Allen's web site.
The project uses the BHI module (NEDSP1061-PCB) as its core build component.
BHI web site -- NEDSP1061-PCB Datasheet
DSP Speaker Material List (Mouser, Digi-Key, Parts Express, Pololu, etc.)