Let me start by saying that I've read countless threads and tried my hand at winisd, but I'm not having much luck so I'm asking for assistance. My project consists of 1 15" TC Sounds TC-3000 DVC driver, 2 15" vmp passives and 1 18" passive. I know it sounds a bit off that I'm not using the same size passives but the simple explanation is that I could not find a second 18" after purchasing the first one. After bracing and displacement, I'm working with 4.8 cu ft and would like tuning @ 16hz. I'll be using am antimode 8033 for room calibration. So I guess I'm asking for help calculating how much weight to add to the passives.