Best multi-purpose subwoofer

How are the REL subs? Earthquake Supernova?

ghulamr,

     Are you ruling out a Swarm type bass system?

     If it's too expensive for you, I understand.  Prior to the Swarm, I tried multiple brands and models of single and dual sub configurations and positions in my room ( Velodyne, REL, JL, Hsu, Klipsch, Polk, B&W, Theile and a few others) and none performed as well as the Swarm.
     My main speakers and center ch are Magnepans, which are notoriously difficult to integrate subs with.   The Swarm system was the only system I tried that blended seamlessly with the Magnepans for music and still delivered the bass impact I wanted for ht.  It truly is a state of the art bass system. 
     I'm unaware of any single or dual sub setup using conventional subs, at any size or price, that can match the performance of the 4 moderately sized Swarm subs properly positioned.   I do believe, though, that utilizing 4 of almost any top line conventional subs properly positioned in a distributed bass array system would likely outperform the Swarm subs.  I've never personally tried this but I know it would cost about 4x or more than the $3K price of the Swarm and probably only deliver marginal bass response improvements.
     The 4 sub distributed bass array system is the result of years of research on in-room bass response conducted mainly by 2 PHDs in acoustical engineering, Dr. Earl Geddes and Dr. Floyd OToole.  Google their names if you'd like to learn more about their experiments, conclusions and White Papers.
     My intention is to share my many years of experience and knowledge trying to achieve the same bass response it seems you're now searching for.  I have no financial or other interests with Audio Kinesis/Swarm other than purchasing their bass system and knowing how well it works in my system.
      My opinion is that the single 15 x18 x20 sub that you are looking and hoping for does not exist.  Sorry, but it's as simple as that.  
     The $3K Swarm system is the least expensive solution I'm aware of that will provide you with the bass performance you described.

Tim

The storm is just 4 10 inch passive subs running off one 1000 watt amp.  
 Its pretty commonly known that 4 subs is an ideal setup for home theater,   I would get 4 subs and dsp and could be under the price of storm all day long.   And have dsp....

Never really heard of the Swarm. The website seems weak without much info and it’s not been mentioned or written up elsewhere besides AS. Also the set up for 4 not being wireless means running wires all across which is definitely a no. 
I’ve narrowed down my choices to REL, Rythmik, SVS for the smaller dimensions. What is hate the most and it’s true the larger the woofer and better the room is pressureized. I am locally getting a 15 inch earthquake supernova - a very tempting offer. 

Rythmik, HSU, SVS, JTR, PowerSoundAudio (co-founder of SVS). With my preference being the first two.

I don’t think anybody makes better subs than these brands in regards to bang for buck (the >$10,000 JL Audio Gotham is hardly worth it other the $2300 Rythmik G25HP).

Well, also should mention BIC and Dayton for entry level budgets.

However, not all models from the brands mentioned take high level inputs.  
  
REL is garbage for home theater, even their >$7000 flagship is only -6dB @15Hz in-room. That’s is pitiful, even the cheapest sealed Rythmik is -6dB @12Hz anechoic.