If you get a 10" Logan, buy the earlier Dynamos used, it's what I have. They're sealed rather than ported and by all accounts more accurate than the current model. For what you'll save buying used, for the money you can get two, always better sounding than one sub. I saw one for sale the other day at a very attractive price, it may still be up.
At the opposite extreme, consider this, it's more expensive at $850 but highly regarded and it will take you all the way down to 20 Hz with good output and servo control:
http://www.ascendacoustics.com/pages/products/subs/f12se.html
At the opposite extreme, consider this, it's more expensive at $850 but highly regarded and it will take you all the way down to 20 Hz with good output and servo control:
http://www.ascendacoustics.com/pages/products/subs/f12se.html