I use Svs 400 subs which are sealed And very fast and articulate
they have a verygood app you can adjust from your tablet or phone
you didnot mention the frequency response of your speakers ,
for some movies or even music with poor recorded bass just turn up the volume as needed ,you want your Bass to blend if your speaker says plus or minus 3db at say
40 HZ add 10 db and then godown 1 db at a time ,you want to get the most out of the main speakers , to get good fill and still have seamless Bassfrom the sub.
you don’t want over lap ,that's why +10 db is a good start ,and many mfg
pare not accurate in their measurements ,there is no. standard on exactly wen the frequency starts rolling off ,many mfg are not totally truthful.
if you bought a much better sub you would hear much more articulation in the Bass notes. Sealed subs are faster then ported subs as well as more articulate .
look at JL audio fathom , Wilson ,Myself Svs 4000-SB , the Rel has a open passive radiator similar to a ported sub more boom ,