I have started a new subwoofer project. I have decided on using the HSU driver because I do not like how Shiva's make that loud Popping sound when bottoming out and HSU's in my experience do not make that type of loud startling noise when they bottom out. Anyway I was thinking of making a sealed design. Has anyone here ever constructed a sealed HSU subwoofer? If so how do you like it? How well does it perform in the low end? I was planning on using several drivers. Also does anyone out there know how to calculate the total Q of a sub given a box size? Also with a VAS of 140, does anyone know the optimal box size for this driver, or how I can find out?Programs like WINISD do not seem to be accurate in calculating SPL loss in sealed boxes from my experience. Thank you in advance for your responses. Also any further suggestions would be appreciated.