To tame your small room with pinpoint accuracy of low frequency tones the best sub choice you already made is the DD go for a used DD 10 or you can go for the cheaper velodyne spl 1000R. both have excellent equalization option.
The JL Audio may produce a little more bass at high volume which you seldom may use but the sound equalization settings are not so great.
The JL Audio may produce a little more bass at high volume which you seldom may use but the sound equalization settings are not so great.