The sub doesn't get destroyed by plugging the port. That's nonsense. It's quite the opposite. By plugging the port you prevent the sub from mechanical damage. Audyssey doesn't care about the type of sub and might boost frequencies below the driver's resonance frequency. In any vented sub design such a boost can lead to potential damage of the driver (voice coil hits the pole plate).
Again, you don't get better sound quality just by using two subs. Modal decay is as important as frequency response. Near field subs give you better modal behavior whereas multiple subs don't guarantee faster modal decay.
I'm not implying in any way that your not giving me useful advice in most cases - and I do appreciate the suggestions on my behalf to help me improve my overall sound quality! so thank you for that .. But I think I'll err on the side of caution for now. To be honest, directly behind my couch isn't an ideal position anyways, and with the size of these cylinders, that particular position would not only be slightly problematic ( always banging my bike into it I suspect ) but also quite the eye-sore. In any case as you said without getting the driver closer to my head, the nearfield setup won't work. I can't very well turn the cylinder upside down ...It definitely looks like that wouldn't be good for it - besides making it look completely ridiculous lol.
I dont think you'd destroy the sub, but as it was specifically NOT designed to have the port plugged (unlike the other cylinder subs from SVS) I'd personally be very careful about blocking the port. If SVS had intended this sub to be run with the port blocked I am sure they would have provided blocking plugs as they do with the other subs. ICBW, but I think it's best to err on the side of caution. Or at least drop SVS an email and ask their view - IME they reply to emails almost before they receive them
I think a second sub can help in various ways, but it is usually used to smooth the bass response and create better bass over a larger area of the room. I found that adding a second sub was the only way I could deal with my room modes satisfactorily and achieve much nicer bass quality (rather than quantity). I ran dual PC12s up to the time I bought the dual Submersives.
I think that's my best bet at this point. Though I'm rue to spend another 800 ( with tax and shipping ) in less then a month, when I started out just wanting one PB1000 at 500.00, It'll be a thorn in my craw knowing I've got a huge dip in the bass response. I probably would have been better off NOT measuring it and not knowing I was missing that much, but the genie's out of the bottle now - so I'm going to have to bite the bullet.