You can see the bass section in my avatar, but I'll post a larger picture here too.

The woofer in this 3-way is the Dayton RSS315HF-8 which accounts for about 25% of the build cost with the Scan Revelator mid making up the bulk of the cost. On the back of the cabinet is an Acoustic Elegance 15" Passive radiator which tunes the 3.3cf enclosure to 17Hz, which gives anechoic F3 of about 25Hz and F10 of 14Hz. The bass produced by this excellent woofer, which has loads of copper in the pole piece for low inductance and distortion, is effortless, warm and enveloping, and when called upon, will rattle the walls. I've got it crossed to the Revelator at 350Hz 2nd order. This is a true 3-way with passive crossovers and time aligned baffle. Needless to say, there's no need for a sub.
It's all powered by a 500W Class-D amp.