Ive found that in the real world the push/pull configuration offers superior performance. I tried both push pull and dual opposed and the PP just sounds like it has more slam, more authority and a little more effortlessness to the sound. Ive tried this with a friend as well and a further 3rd person tried it with his DIY dual driver sub, both were convinced I wasnt talking rubbish and the push pull is superior to a simple sealed twin driver sub. IMHO, the only way to do a sealed sub is push pull, and I prefer this design above all others. A push pull sub with 2kw will have 6db more max spl capability over a single 1kw single driver sealed sub, and the performance increase Ive experience I guess can only be attributed to the harmonics cancellation effects that are documented. Ive also found the sealed PP sub to be the most accurate Ive heard and I cant really say anything bad about the design myself.
The negative design points of sealed subs still exist, and the way around this for us is to use very high quality drivers and lots of power. The driver certainly look the part, and models incredibly similar to my drivers which Ive been simply amazed by. Power wise, I would certainly use more than a plate amp can offer, especially as you need to power both drivers from a single amp. Add to this you get a lot more power for your money with an external pro amp (which can easily be swapped should you wish to experiment), and you ensuring you maximise VFM.
When it comes to size, there are a couple points you need to take note of. A push pull doesnt reduce required volume per driver. Whatever your drivers volume requirements are, the push pull requires this same amount of volume per driver. A twin driver sealed sub (and a push/pull is a sealed design variant) requires exactly twice the internal volume it would for a single driver design. A sealed sub is generally smaller than a ported on though, so you will enjoy size minimizing here.
The other point of note with a push pull design is that one of the drivers has its voice coil external to the cabinet. In order to keep this part (which no body really wants to look at) hidden from view, you need to increase your cabinets overall dimensions to include this rear part of the driver. This is the reason my subs rear driver is placed where it is. It gives me the volume I needed whilst keeping the external dimension as minimal as possible. A true opposed alignment will inevitably lead to the external cab dims having to be increased if you want to hide the rear driver, otherwise you will be able to see it, so its upto you how you would like to manage that part of the design.
IMO, push pull is certainly the way to go, but if you went with a normal push push dual opposed design the overall cabinet dimensions will be slightly smaller. You really need to figure out which is for you in that respect.
When it comes to position in your room, obviously proximity of a driver to boundaries increases the boundary gain effect, and the lower driver in my sub fires directly into the point at which 2 boundaries meet. Ive found my sub in my room enjoys a cracking amount of low end room gain, that once EQ is applied makes it flat to beyond 10hz right upto reference volume on my amp. If anything I could use slightly better power but what I have right now rocks in my room. Having a driver firing into a boundary or two is IMO actually going to help this sub design couple to the room better, and certainly Ive never found a sub fill my room in such an even way, especially after EQ. In short, this design, in my room, has offered me the best performing and most musical sub Ive ever heard to date, and in a package that isnt obscenely huge. I think you could do a whole lot worse than following this design.
Hope that helps with the basics a little, if there is anything else I can help with just ask.
