enclosure reccomendation?

first off HI! im new to the forum, polk pwnz! :biggrin:

i bought a single db1240 (single voice coil) and need help finding a ported box to match this sub.. i been doin research but i just dont understand what it means to tune a box to a sub...

can any1 recommended a ported box that would go well with the db1240 to keep the sound quality? because ive read everywhere that ported boxes wont have as good sound quality as sealed unless its tuned properly.

the amp i'm getting is the PA500.4 and will be bridged for 250 watts rms to the sub.

the other 2 channels are going to be wired in series to all 4 db401's