In my opinion the top two subwoofer manufacturers are "REL" & "SVS". I have not heard any other sub drivers hit low frequencies with such crisp-expanding bass. These subs really change sound dynamics.
Now, with that all said I came across a fairly new REL Q108 MKII Sub Driver for $25 and had to buy it. So, now I going to hone my building skills and construct my own subwoofer. I have some idea of what kind of box I want to build (enclosed box for sure), but I like to hear from anyone that has any ideas or delt with building a sub box using a REL driver.
Thanks