This is what makes the DIY so much fun! My finished system is what I've been looking for!
I spent about 4 hours researching multiple sub locations and proper phasing and testing. There was one extreme to the other on suggestions, but the most mentioned with good reason, was the co-locating of the two subwoofers. Reports indicate that there is a 6 db gain with this placement, and I'm a beleiver. Joe Satriani has four bass guitar quads stacked on both sides of his sound stage for a reason. I just figured out why. I stacked them on top of each other and there is a tremendous gain resulting in this configuration with all of the drivers working together instead of cancellations from each other if they were to be located on different sides of the living room. The living room is 18' x 24' with 9 ft. ceilings and opens up to the kitchen and dining area. I've also got a nice clean corner location for added room gain.
I now have 12-15" active and passive drivers working together in the same corner and I'm at the point to say I think I could have too much clean bass now. I have reduced the gains on my amps, reduced the db gains in the Rotel set up program, and the output is extremely more pronounced. I've bumped the crossover point up to 60 hz and the mains are producing cleaner sounds than I've ever heard. They are not having to carry the 40 to 60 hz range which is quite a load. The QSC amps are blowing out cold air meaning they aren't working as hard. I've cut them back by 30%. This will also save my drivers as they don't need as much power as before.
It's all a win win situation, but I'm going to have to live with a tall subwoofer. I'm leaving the grills off the lower one until the upholstery shop finishes covering my frames for the top one so it won't look funky in the mean time.
I now think I have the ultimate sub setup. The WAF has not been affected. When I told her I was going stack it, she said to get some help. When she got home, I reminded her of the don't ask and don't tell policy. Each subwoofer weighs 235 lbs. It was a chore indeed to do by myself. I had to take the picture down behind the sub, but she will find a place to move it.
The output is absolutely stunning, clean, undistorted, loud (if needed) and very low. Thanks for the support from the forum members, especially to Mike P. who figured the tuning frequency which came out to 23.5 hz with WinIsd. I tested it and got a good reading of 23hz using Vance Dickison's instructions. It gets much lower than 23 hz. though!!
I used a Granite Audio bass test CD. I am sold on the passive radiator design because of its clean undistorted and lack of a resonant sound that can sometimes be heard in a ported system. You pay dearly for the design though.
Mike Cason
