@larry5729 , it is painfully easy to beat Rel subs. The problem is the only commercial manufacturer to do it is Magico. A private citizen that is a competent wood worker can do it with their hands tied behind their back. You use balanced force design like Magico and make the enclosure even stiffer.
@parker65310 , I used DIvas for 6 years or so and I could never get subs to match perfectly. This was before DSP came along. I returned to ESLs and with DSP have no issues with integration so, I am sure with proper digital bass management it will be easy and a huge benefit. Like ESLs ribbons do not like making deep bass. They can do it but they do not like it.
@ieales , Rel subs are made as well as any commercial subwoofer. If you are comparing them with other subs on the market. They have two issues. I hate their method of integration and it is easy to get better subs if you build them yourself. I can do things that are totally impractical if you want your sub to come in at a reasonable price and take less than a century to build. I am not trying to pump up my ego either I mean this in all sincerity. I can do better than the subs I have now but the fellow that calibrated my projector (this is his real profession not a side line) related it was the best bass he ever heard. Frankly, I think they are ugly and a bit soft. It was a good performance for 20 years ago but I have learned a lot since then and am in the process of building a new set. Unfortunately, they are competing will things I have to do for the wife and the wife always wins. It is going to be a little while yet. I was hoping this Summer. Time Waits For No One.