Subs don't have to be "fast" (a bass note is quite slow in attack) they have to be "clean".
A lot depends on where you are crossing over. If you are crossing over at, say, 70hz or below the HSU VT3 is invisible and has great deep basss at around 800 bucks. If you are crossing over at a higher frequency I might rather go to a sealed box type. The Martin Logan ones are very nice (if pricy).
The trick is, the decay characteristics of the sub have to match the mains or it just doesn't gell. For instance, my speakers only sound integrated with ported subs; sensor-controled and sealed boxes just would not match no matter what I did. On the other hand my friends sealed box speaker sounded best with a sealed type sub.
A lot depends on where you are crossing over. If you are crossing over at, say, 70hz or below the HSU VT3 is invisible and has great deep basss at around 800 bucks. If you are crossing over at a higher frequency I might rather go to a sealed box type. The Martin Logan ones are very nice (if pricy).
The trick is, the decay characteristics of the sub have to match the mains or it just doesn't gell. For instance, my speakers only sound integrated with ported subs; sensor-controled and sealed boxes just would not match no matter what I did. On the other hand my friends sealed box speaker sounded best with a sealed type sub.