For anyone delving into the open baffle woofer realm, skipping the Alphas, Deltas, Goldwoods, etc can make a huge difference in the quality of the final product. If you want to step into the highend, I'd go right to the OB woofers made by Acoustic Elegance. The difference will be one of the least subtle upgrades you'll ever make. The Alpha's are a good introduction, but in the real world, I couldn't make myself happy with them with numerous attempts. The suspension is very non-linear and with the already limited xmax, that's not a good thing. If you look at the klippel measurements for the Alphas that you can find on the internet, you'll see that cms gets a good bit stiffer through the rated stroke of the driver. Outside of a couple of millimeters, it measures completely different.
Also, while dipole bass is *slightly* less room dependent then some monopoles, the response is still very much dominated by the room. Room modes were still very clearly heard and measured in each of the rooms I used my various dipole subwoofers over the years. Luckily, standard distributed bass systems match up perfectly with dipoles and monopoles alike.
