IMO, the Lava LSP12 is far better than the Polk, Sony, and Klipsch subs that are sold at Best Buy (that are roughly the same price or more than the LSP12). I have listened/owned most of them so I know.
The LSP12 doesn't sound like a rolled up newspaper hitting an empty 5-gallon bucket at spirited SPLs like most of the Best Buy subs do. The LSP12 also goes louder.
The LSP12 is no where near as powerful as an Epik Empire, and doesn't even scratch the surface of how low an SVS Ultra can go.
IMHO, the LSP12 (~$300) is a good sub for the price. No, it's not an SVS PB12-NSD ($699), but the Lava is half the price of the SVS. According to Illka
, the PB12-NSD had a maximum output of 105dB at 30Hz and 108dB at 40Hz. If my memory serves me correctly, I only achieved peaks of 105dB (uncorrected) during the WOTW pod emergence scenes.
That said, even dual LSP12s will probably not get you the the SPLs at 20Hz (even with EQ) that a single PB12-NSD can achieve.
Just some random thoughts on my part.