These speakers were designed to be a low cost yet high performance bookshelf or stand mounted speaker which has enough bass to stand on it's own when placed out into a listening room. However the design should allow near wall or shelf placement without the bass becoming boomy or overpowering. To accomplish these tasks, I selected the Seas 27TFFC tweeter; a very good sounding, yet inexpensive tweeter. The midbass driver I selected is the Seas P17REX, which is a heavily over-motored 6.5" polypropylene cone woofer. This is a very good sounding inexpensive driver as well. The midrange sounds a lot more like a paper cone driver than a plastic one. I decided to try a bit of an unorthodox box loading for this design and use a 6.5" Seas passive radiator.
The pictures shown below are of my prototype pair of speakers which are finished in a laquered cherry veneer. The boxes are constructed usign 3/4" MDF and 3/4" baltic birch plywood. The boxes are stiff and rigid as a railroad tie; very dead and uncolored. The prototype crossover is constructed on a custom designed FR4 glass epoxy circuit board using 16 gauge air core inductors and polypropylene capacitors.
The enclosure construction plans, crossover design, and prototype measurements are shown below in three Adobe Acrobat files.
Seas Bookshelf Enclousre Drawings
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