I made some with the cabinets and crossovers from some old Sharp speakers that came with a 70s music centre, and some drivers from Celestion, plus a lot of foam glued inside the cabs from an old armchair.
My methods were not very scientific.
I just kept testing and cutting away, moving or adding foam, tuning them by ear until they sounded kick-ass. Still using them 15 years later.
I like this story. Hacktastic.