I have been learning a lot the last couple of weeks from this forum about speaker building. This is my first post, any help would be appreciated. I am looking for suggestions for a DIY sub plan. I have a large room that is not set up very well for home theater. It is open on one side and the back is also open. The house has an open floor plan with cathedral ceilings about 10 feet high. I have Def Tech BP30's in the front and BP20's in the back with a 250 watt Carver Amp driving the mains. I have a 125 watt 10" Nuance Sub that does not do the job. I listen to both Rock and movies about 50/50 split. I like it loud at times! I am considering building a ported design, SBB4 from Adire Audio with the Tempest driver and a 250 watt amp. I think that would give the extra punch I need. I am experienced at cabinet making but not speaker design, so I would rather go with a proven design. Does anyone have any thoughts on this?