About a year and a half ago I did a build of a small open baffle three way using GR-Research drivers. I can't get into the details at the moment but it is based on an experiment that Danny was working on at the time. The drivers are the M165X performing the bass duty, the M130X in an open baffle configuration operating from 200Hz to about 2.5Khz, and a B&G Neo3PDR tweeter at the top end but acting as a monopole.
http://s710.photobucket.com/albums/ww110/bschucha/They measure pretty well but I did design in a BBC dip which, long term, I might remove at some point. I say "might" because in my small listening room the "in room" response with these is surprisingly decent.
Overall they work great and sound amazing when in the sweet spot but I can see why Danny uses multiple bass drivers as a single M165X can get hammered pretty hard if I don't use bass management. Next time I may use an 8" woofer and mount it further from the floor or use multiple woofers for the bass.
After listening to these for an extended period of time I can see why Danny has the OB5 and OB7 speaker kits as they suffer less from compression on the bottom end. That being said, the small size of 8.5" by 36" and with a small bass module at the bottom gets them enough points to be allowed in my small listening room.
Something like this is definitely an option for those looking for some great sound but limited on the size speaker allowed in their home.
http://s710.photobucket.com/albums/ww110/bschucha/ Bill
