Looking for a non-powered sub

Thanks, I`ll look into that.
Any $500-800 DIY subs out there that can compete with the better known commercially available ones?

I do have an amp that I want to use. It`s a Behringer EP1500.
I`m led to believe that to blend in a planar well, some outboard devices might do an overall better job.
Problem is, I don`t know what all I`ll need,and keeping the cost on the lower side of it all too.

Gallant, my room is only 14' x 18' with 9' ceilings. Dipole subs might be pushing it don`t you think?

Java..No interest in wood working, but a put-together kit is interesting.
I`m leaning to the VMPS especially if they can be had in kit form.
In the VMPS line, which sub would you recommend in my room?
I want tuneful/musical bass, not what I hear going by me on the road if you know what I mean.

Which crossover would you use to limit the 1.6`s from seeing too much bass a Paradigm X-20, NHT X-2 or other... ?
Thanks,
Steve