Open Baffle vs Box

gochurchgo, what you get is a confused mess lacking in both punch and rumble. As the wavelength of the reproduced sound gets longer than the driver is wide the sound gets increasingly more omni directional. The wavelength of 100 Hz is around 10 feet, far longer than a 12 or 15" driver 
is wide. The rear wave of a woofer is 180 degrees out of phase with the front wave and both are omni directional. They cancel each other. Stand directly to the side of an open baffle woofer and there will be no bass. Now depending on the distance to the front wall the rear wave will bounce off the wall and come back at you at a different phase angle and things get more confused. Contrary to popular belief increasing the size of the baffle board does not help at all. Low frequency sound is very powerful and can travel long distances in air. Ask anyone who has been within 10 miles of a plane breaking the sound barrier. 
For all the difficulty in building a proper bass enclosure the results are well worth it, even more so given modern high power amplifiers and digital bass management. So why wouldn't this work with dipole sub woofers? Well, when two sound waves 180 degrees out of phase sum you get zero. More of zero is still zero.

Above 100 Hz open baffle speakers can be great given the right drivers. It is much easier to build a plate that does not add colorations than a box.
All of my favorite speakers, the ones that I would own are boxless. Under 100 Hz is a different story. The problem is that building a SOTA subwoofer is an expensive and difficult task and the end result will be a device that is very heavy and expensive to ship. Most manufacturers cut corners resulting in flaws that for those of us who have experienced the best bass find intolerable. I believe those of us with DIY capability can actually do a better job than most manufacturers but in forms that could not be competitively priced.