DIY Sub...1804 vs tumult

[xl8ed]

Hi All,

As I'm completely new to the DIY speaker building process, so I'm turning to you all (the experts) for help and advice.

My prequesites for the sub(s) are
- clean and well controlled bass ie 'boom free'
- able to play quite loud down low (15hz)

I intend to use them primarily for home theatre use, however they may be called on for the odd song here and there where a little something extra is required

Initially I was looking at the Aura 1808 (now seismic) drivers (ala Wilson XS) and North Creek Leviathan (based around the 1808 motor), however it would seem that I might be better served by a more up to date and cheaper driver such as the BluePrint 1804 or the Adire Tumult.

I'm leaning towards two 1804 based subs powered by a QSC amp and a BFD
(http://www.hometheaterforum.com/htfo...hreadid=195667).

So here come the newbie questions.....
- what's the purpose of the BFD?
- would I require a ULTRACURVE PRO DEQ2496 or is a FEEDBACK DESTROYER PRO DSP1124P sufficient?
- What size/type of enclosure would best suit my needs?

Any other constuctive comments would be appreciated.

Thanks,

Nick