Who are some of elite sub woofers?

Looking to replace Klipsch 12d

So many choices.
The facts prove that subwoofers are not used the right way all over the world. During all audio shows, you hear the same flaws. Most subwoofers are still used without an acoustic room-correction system. Others use the measurement system which is a part of the subwoofer.

But in all these situations it is 100% impossible to get the perfect integration. When you would test the subwoofer by simply switching it on and off, the sound and stage will even prove the flaws. But people have almost no insight and knowledge in sound. So for them is it never possible to understand why it is not good.

Human beings are very easy to persuade with assumptions. They often will take lies as a given and a truth. In the world of audio, there are still many assumptions which are believed as truth. But, the sound can prove that many assumptions are chosen wrong on facts.

When you switch the subwoofer between on and off you will hear that voices and instruments will often become bigger in size. And you will hear often that the individual focus of voices and instruments will become less sharp and palpable.

You need a room correction system that can measure both the loudspeakers and subwoofer together. Then you can get the subwoofer in phase and it will understand where the loudspeakers are standing.

This will create a superior level in result and integration. We call it Stealth Low Frequencies. It will blow your F. mind. The energy is there where it is on the recording. When you sit at your chair, you will always feel the energy of the low. frequencies fully separated from the loudspeakers. It is even separate from the subwoofer. This is the Reference level in using any subwoofer.

I will not use names, but almost all subwoofers in the world are still too F.slow and use materials that are not light enough. The response of the drivers is still too slow. Timing is an essential part of all subwoofers.
JL Audio.  All the adjustments you need to perfectly integrate, a flat response that covers the notes in music (not just one!) and powerful amplifiers that get the job done.  
You can create a higher level in realism with a subwoofer in phase than any system without a subwoofer. In the past, I was never interested to use a subwoofer for stereo. But when I was able to use a room correction system that measures both loudspeakers and subwoofer together a new world opened. 

This world creates new levels in realism in sound which were not possible without the use of a subwoofer. To be honest I never thought that we could integrate a subwoofer at this level of precision. 

Hi bo1972 
    I watched your reviews about power cables and Tru Fi . I appreciate the new approach  You used the Dragon power cable for the sub woofer for a "DNA" on this cable, capable of generating low immersive frequencies;
       I would have three questions about the Dragon :
    Would it be superior to the Hurrican power cable in low frequency and bass generation if would it be used to power an amplifier? (eg Hegel H 300)
     Is the Dragon generally superior to Hurricane or does it have certain valences that make it more relevant on certain areas of use ...?
     You said you should get Firebird to test them; if you had the opportunity to make auditions with Firebird where you would put it in comparison with the two, Hurrican and Dragon?  Thanks a lot for the answer
SVS x 4 of whatever model[I have 2 PC-2000's].2 of these would be in your budget
HSU good too and I don't think you could go wrong with either .I haven't heard any of the others mentioned but would try REL based on Pauls[ PS Audio] recommendations.