Bought the wrong subwoofer!

I had one of the old Rel subs. I rebuilt the amp and the woofer needed to be replaced at about 20 years. I ordered one from Volt in the UK, they still make the same driver.  It was a good sub.

I think bass is one of the last things audiophiles understand so I’m glad there are so many subwoofer experts on this site. 

I think bass is one of the last things audiophiles understand

I remember a time before subwoofers. Never had a sub nor needed it til 15-20 yrs ago. But I remember back in the late 70's early 80's when the notion of taming down the bass so as to get a cleaner sound and better midrange. Then over time it seemed that bass became so unimportant that it was pretty much stripped from the mains. my speakers specs say 20-20K. But without the sub the are sorely lacking in bass. Midrange to die for but little real bass...especially for R&R.But WITH the subs they are fabulous. So we lost bass, then we created a new business for sub woofers. They tell me this is progress

I think bass is one of the last things audiophiles understand 

That's for sure. Virtually all of them are still stuck in the understanding exemplified in this thread. OP went from one sub to another, swapping when he should have been adding.

Low bass is near impossible to do, for the simple reason you cannot fit 50 foot long bass waves into a 20 foot long room. The wave reflects and comes back and cancels itself before it even gets going. For many years I tried everything and never heard anything work properly and had given up. The physics are just too daunting.

Until a couple years ago on this site Tim (noble100) and some others were talking about a Swarm or Distributed Bass Array. Do a search for these if you want to understand low bass. Read everything you can find by Tim and Duke. Read the research paper and doctoral thesis that started it all. 

While you are at it check out the dates of the papers and discussions. Then reflect on how slow people are to change and learn and adopt new ways of doing things, even when clearly superior. Everyone who has been on this site more than 2 years knows all this. Half a dozen of them should have chimed in by now saying don't swap, add. Instead, crickets.

I think bass is one of the last things audiophiles understand 

Duke, Tim, DBA. Now you know how to not be one of those audiophiles.