I'm thinking about doing that, it only seems logical if I don't want too much bass but more than I've got, this would be the way to go.
th ebox building for the airspace it needs would be funny, but do-able i tink.... i took some measurements...lemme go find em..
i started looking around and fosgate has just the speaker....maybe P18S4 8" Punch P1 4-ohm SVC Subwoofer Bass for a small space! Optimized for small enclosures, the P1 8" subwoofers are a perfect addition when space is at a premium. Their shallow mounting depth offers a wide variety of install options as well. a sealed enclosure needs to be 0.25 cu ft or 7.08 liters mounting depth is 4.125"