Hey, I'm interested in building a subwoofer with a driver I have. Though I'm not sure where to find good software for designing it or even where to really begin. Please help. Here are the specs. Bumper 450 watt speaker Qes: 6.34843 Qms: 3.61839 Qts: 0.31782 Vas: 5.85 cubic feet fs = 24.15Hz Diameter is 15inchs and the diaphragm is 12 inches With the Qts value its has to be a ported box, and I'm not really sure what to do though. Would a 300watt RMS amp be sufficient? Any help would be appreciated btw would a sonotube work good?