I've tried several OB's over the last few years and while the mids and highs were great they were lacking in low frequencies. Several months ago I came upon Martin J. King H-frame designs and decided to give them a try. MJK BTW is a true genius in speaker design and has a cult like following on DIY Audio. I built the H-frames and added the Tang Bands in an upside down T arrangement and I'm here to tell you these things are beyond amazing. Now my OB has a great bottom end to go with to die for mids and highs. The H-frames are not like plodding subs that can't get out of their own way, they are musical and reproduce the low end of a string bass better than I thought possible.