Looking for the top 3, 18" subwoofer drivers closest to the LMS-5400. This is for a large enclosure with one or two 18" passive radiators. The sub will only be playing 50hz and lower. If I can get my main speakers tuned down to 40hz, I would only be playing the sub below 40hz. That's the goal. I'm also looking for 18" passive radiators for this project. This won't take place till late in the year but I'm just trying to take my time and do my home work. Thanks.