Hello Ryder I have had many subs , a perfect example was ihad the Svs SB 3000
i bought the SB 4000. It was just more powerful and ease in the Baer more articulate , notnight and day , but enough to sell the sb 3000
i had my brothers Svs ultra 16 which is the big brother to the sb400 and it was slightly better still but too big for my space being almost 2 ft deep and over 200 lbs
the driver in the sb 3000 is around 24 pounds,the sb4000 44 pounds , and cabinet much more ridged it weighs 102 lbs , the Svs App is excellent and allows you to adjust bass on the fly ,for many recordings either have too muchbsss or not enough.
where Rel are not sealed ,they are more efficient ,less power for they are like a semi port, using a passive radiator firing down , Sealed boxes have a bit better control comparing , in my friends system hisJL audio Fathom 12 , with true auto room correction with Mike you just plug in $5 k retail it should be special ,,