Subjective
From a marketing standpoint, I’d have to guess that the X412 is aimed more or less at the SPL end of things. It’s heavily built from almost any perspective and has that “I am bad-ass, hear me roar” kind of appearance. However, SPL is pure physics, so we’ll have to wait and let the objective specs speak for themselves.

As tested, the X412 sounds like a sub for the relatively sane. It doesn’t threaten to rattle your fillings loose on boom tracks or threaten to smack them out on audiophile tracks. The rattle part could probably be changed with a tuned box, but most people don’t consider dental work when they buy a sub. The X412 seems to prefer heavier, beat-driven stuff without sine sweeps and huge bass hits — you know, regular music. It sounds a little thick in the upper bass range compared to our reference sub, but let’s face it: that’s what most people like and it does work well on most types of popular music.

Objective
Impedance measurements for this system show a maximum of 30 ohms at 54 Hz and a minimum of 4.8 ohms at 20 Hz. Average impedance measured 8.8 ohms. Out-of-car response shows a rise of about 6 dB below 100 Hz, followed by a 12 dB-per-octave roll-off below system resonance. With the exception of the node in our test vehicle at 72 Hz, in-car response is smooth and extended. In-car sensitivity at one watt averages 93.2 dB between 10 Hz and 50 Hz. At 300 watts, the sub exhibits about 2.5 dB of power compression and produces a maximum SPL of 121.9 dB at 50 Hz.