I've been using Lspcad but I don't think it can calculate the Q of a box. I've been thinking about the optimum height for my 24" diameter sonotube with my AV-15. What height would give me a Q of 0.5. I'm going for tight, accurate bass, and I think that's what you guys were recommending. I've got a sloppy EBS tempest which I've tried stuffing with no success, so I figured all try again. This time I'll brace the top and bottom endcaps.