Upgrading sub to get a live feel.

thewatcher101,

     You may be able to improve the bass response at your listening seat just by repositioning them.  I'd suggest using the crawl positioning method sequentially for each.
     If this doesn't work and you have the room space, using three SVS-SB1000s, sequentially positioned using the crawl method, is virtually guaranteed to provide bass response at your listening seat approaching state of the art.  This is called a distributed bass array (DBA) system and it works amazingly well in virtually any room and with any pair of main speakers, even with faster and very detailed speakers like electrostatics and Magepans.
      The bass perceived is very smooth, detailed, as powerful and dynamic as the music requires, seamless integration with any pair of main speakers and an overall quality of effortless bass on music and HT.
      I use a 4-sub DBA system called the AudioKinesis Swarm in my 23'x16' room with large Magnepan panel speakers and it works like a charm.  The DBA concept usually requires four subs to function properly but works almost as well with three.  
     Here's an Absolute Sound review of the AK Swarm that gives a good explanation of how it works and what to expect.  The SB-1000 subs are ideal to use in custom DBA systems because they're very good subs and are relatively small.

https://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/ 

Tim 

Thanks a lot I will look into it.

i also believe that the mids and lf are the most important part of music.

i currently have the subs right under my main speakers. They image very well but still lack that physical presence.

Room acoustics and EQ matter a huge deal. More so than the sub hardware itself in a lot of cases.

Tim is right about the DBA/Swarm subwoofer solution. The one I built with 4 Morel 10" woofers and the Dayton amps for under $3k gives more powerful, deep, articulate and smooth bass than anything I ever heard anywhere even from vaunted state of the art speakers costing ten and twenty times as much. Using four subs spaced around the room works so much better than the old-school paradigm of one or two that it doesn’t hardly even seem to matter what quality or how much you spend, until you get to three or four you’re just never gonna get there.

I am going to join in the camp that says look at your placement and room setup before you replace your subs. That said, it is entirely likely that your subs are running out of output relative to your main speakers, which are capable of large dynamic swings. If you look at the output of the SVS-SB12 NSD (the prior model), you will see that its max output at 25 hz is 96.3 db, 31.5 101 db, and 40 is 104.6 db. You have a pair, but they are not co-located, so figure 3db more.

https://data-bass.com/#/systems/5b11db42a201f10004e39d7a?_k=8inm1d

With this in mind, it is likely if you are listening at higher levels you are running out of output. To get a set of subs that will keep up with your current speakers, much less the 4367 at full chat, you are going to have to go much larger. Whatever you get, use at least a pair, and if you have the room and money, four (distributed bass as discussed above) A few I would consider:

I think you are on the correct track Seaton Sound Submersive HP, F2, or X21.  Mark Seaton builds excellent subs, as well as monitors which are used by studios and high end home theater and music systems.  I would take the JL off the list.  Very expensive for what you get.  

Rythmik- F18 or FV18- Amazing clean, tight, and huge output. I love my Rythmiks, but I have a slight hesitation, as I think the Seatons may be a better match to your speakers.

HSU ULS-15 MK2- Boring choice, but really great quality subs that sound good and with pair, should just have enough output.

I believe that for any sub you purchase, you should be using a high quality active crossover to bass limit your mains, with a crossover between the subs and mains at about 80-100 hz. I am big believer in Richard Vandersteen’s believe that to properly integrate subwoofers, your main speakers must be linear to 1 octave below the crossover frequency, and your sub one octave above. So here, your mains meet the need, comfortably extending to 40hz.

Finally, while I don’t want to send you looking at another website, you may want to post your question and systems setup over on the AVS Forum subwoofer section. Those guys are very data driven and spend about 100x as much time as people here playing with subs. They often have very good advice on sub placement and setup recommendations. Make sure you give your room size, as it is relevant to output.