Greets!

Hmm, +12 dB is a lot of gain for corner loaded, especially considering the construction. At what frequency is it at? I have similar and only get around +7 dB/stereo corners down to ~25 Hz, then it flattens out as the house becomes a huge absorber.

Nifty electronics, lucky you , these have been on my wish list ever since they premiered.

Why didn?t you post the stuff in your PM? Anyway, referring back to it, a max flat alignment doesn?t have a better transient response than an EBS per se as the latter typically blends in-room better plus has as good or better a group delay above ~35 Hz where we begin to have some LF hearing acuity, which is why many folks [including me] prefer it.

Even better is to use an inverse tapered TQWT that once damped yields as good or better a transient response as a ~IB sealed except with more gain BW. Even my lightly damped ML-Voigt pipes have a perceived bass horn?s ?heart attack fast? response, though of course it?s in no small amount due to having dual ~20 Hz Fs, 0.2 Qts 15? drivers, but with more internal damping this type of loading will considerably ?tighten up? much less powerful drivers.

With MLTL loading, max flat will be a ~30Hz F3/Fb with dual 4? dia. x 0.75? vents, so you?ll need four of them to tune it up around 35 Hz. This gives you a good idea how much even a relatively modest aspect ratio can increase acoustical vent loading.
Regardless, when in doubt I always do/recommend a tuning at least as low as the speakers are likely to be required to reproduce or down in the BW where room gain is taking over, which in your case will be ~1130/2/28 = ~20 Hz [~7? long vent], so at least an ~Fs tuning [~2? long vent] seems a good place to start and use EQ to flatten its higher up BW if it sounds too ?lean? with whatever tuning you choose.

Of course all this is based on specs that?s probably off enough to make these predictions off enough to be audible, but they?re fine for comparisons, finding a starting point.

In my early days of building these types of cabs [they were much higher aspect ratio, so usually folded in half and still 50-60? H] I got so frustrated trying to figure out how much bigger to make the vent to get it within tuning range, finally giving up and leaving a huge, gaping hole way larger than the max recommended driver effective piston area [Sd] or even leaving the entire bottom off, which led me to experiment with bottom firing vents and removable baffle sections long before I ever saw any, so guess I can?t complain

Anyway, short answer is try ~baffle thickness to 7? with one at actual Fs, whatever that turns out to be. The 7? looks about right to me if the +12 dB is at/below 20 Hz.

GM