Interesting.
I haven't heard these speakers. But reading the website I have to say I'm a little skeptical. We see that Vifa XT25 tweeter a lot these days (Blue Sky, Audio Physic...), but personally I'm not a big fan. Its distortion specs are fairly high and it doesn't deal with low order crossovers very well. So, if he's using a lower crossover frequency (2kHz range), he's getting a fair amount of distortion - especially in the 1kHz to 3kHz range. If he's using a higher crossover frequency (4kHz range), then he's going to have some significant off-axis (power response) dip in the 2kHz region due to the beaming of those 7" drivers.
I certainly agree with the sealed enclosure, but I have my doubts about the published specs. An f3 of 31 Hz with 90db/W/m sensitivity from two 7" drivers in a 24 liter sealed enclosure seems, well, supernatural. The only drivers I know of that can reach that low in sealed boxes with those kinds of sensitivities are monsters like the 18" Aura NS18-992. Even still, that unit requires a 200 liter box. I guess Lipinski could be using heavily weighted cones to reach that low in that box, but the distortion levels would be off the charts, the maximum output level would be very limited, and the sensitivity simply could not be that high without breaking some laws of physics. Maybe it's a misprint and he means 90db/2.83V/m? This would translate to 84db/W/m into 4 Ohms, which seems a little more reasonable. The tweeter would also have to be significantly attenuated, putting fewer demands on it, and perhaps making that low order crossover more feasible. Nonetheless, the maximum output level would be rather low - accompanied by significant power compression and low end distortion at moderate SPLs.
Did you notice what kind amp he was using and whether the speakers were able to get very loud or not?
Of course, I've learned to never say never. But I do find those numbers difficult to add up.
Thomas