Originally Posted by mthomas47
I don't think it's a stupid question, or a stupid idea at all.
Adding dual SB12's to the ones you have would net you about 6db at frequencies below about 30Hz, and between about 3db and 6db throughout the passband. And, if you stacked them, in two pairs, they would net 6db more output at all frequencies. That's one approach.
A second approach would be to stack your existing SB12's, and add an SB13 Ultra. You could also try an SB16, but I think that the 13 might be a little better match. I do think that either could work with collocated SB12's, though. What I wouldn't do is to try all of that with your Velodynes in the mix. I think that the frequency response of those subs would be sufficiently different to potentially cause you problems, without some ability to measure, and to adjust the frequency response. So, I would leave the Velodynes out.
FWIW, unless you were planning to spread the subs out around a large room, I would favor adding a more powerful sub, if you can afford it. That would give you a little lower frequency response, and would move you further down the road to a dual Ultra system, at some point in the future.
I Have been lurking the Audyssey thread, and you have more or less confirmed my (limited) understanding. I suspect that if I bought 2 more sb12's, I would be hungry for more. The advantage is I can carry more 34 lbs sb12 downstairs all day. I have SubHT, so anything I do will be in groups of 2.
What I am leaning towards is buying a SB16-U, co locate the SB12, with or without the Velodynes* with the understanding that SubHT will neuter the SB16 somewhat until I can get another one.
The Velodynes are 12 inch sealed servo controlled subs that are, like the sb12's, relatively flat to 20 Hz. They only have a 120 watt RMS amp. before I go buy more, I'm thinking of co locating one with each sb12, set the gain on the velodynes 6 db below the sb12s, and see what SubHT comes up with. If I don't care for the result, I will not pursue it any further. That's assuming my Radio Shack meter still works, I haven't touched it since I level matched the Velodynes to my old Polks about 14 years ago.
And, of course, I need to figure what the separate closest circuit is, I am already causing flickering at high levels, I suspect that if I added an SB16 to the mix, I will flip a breaker!
I also have about 5 spots I can put the 2 sets of subwoofers. Right now, there is one next to each tower, but I do have 2 corners available (right front, left rear) and a small portion of the left wall.
Anyway, like I said in the midst of this musing, is long term, I'm probably aiming for 2 SB16-U. Thanks for your help!