Originally Posted by apnea
Some output from winISD, plotting a single driver in 1.25 cubes (internal) with 500W (over the maximum specs given by Infinity, but we'll see about that.....)
I had to guess at some of the T/S specs, and I couldn't find a file for winISD - I hope I guessed right
Max SPL - not stellar, but I'm in this for the experience, so for < $100 a cab, I'm happy
Over-excursion of around 3mm - I'm not too concerned, should I be? I could wire the 2 voice coils in series to present 350W per driver, but I don't like leaving headroom on the table
I'm looking at putting a single 1262 into 1.2ft3 and saved my design in BassBox Pro. First, here's all the T/S specs on the 1262 straight from Infinity for you -http://us.infinitysystems.com/tl_files/catalog//Infinity/Infinity-Car/Specsheets/Reference/Reference/1262w/REF1262W_PI_EN.pdf
Second, modeling in my 1.2 cu ft sealed file with 500w input, I'm showing xmax is not
exceeded. Xmax does not exceed until 584 watts with coils wired in parallel for 2 ohms. You should be good. Of course, things are always a little different on paper then in reality, but I don't think I'd worry if I were you. You'll know if you exceed xmax and just back off the boom knob a bit.
Third, I don't see any issues with needing a hi-pass filter in a cab this size. My modeling shows it's not necessary.
Now, fourth. It's been a while since I've done sub design and setup. About 16 years to be exact when I was into car audio. But if memory serves, I want to say I remember something about damping and driver control not being as "tight" or "accurate" when we start to get into sub setups below 4ohms. Don't quote me on this, but if this is for an audiophile type setup, it may be worth looking into.
Out of curiosity, have you considered doing a isobaric setup with 2 1262's? Lower response, smaller cabinet, but a slight loss in dB.