The 2 m CEA-2010 measurement of 122 dB at 20 Hz is certain to be a mistake. That would put it equal to the JTR Captivator 4000 ULF or the Danley DTS-10 with LMS drivers on a 12 kW amplifier. When I WinISD model the TC Sounds LMS-R 15", which the Monoprice sub looks to be using, in a very generous enclosure tuned to 18 Hz, I can't get anywhere near what they are claiming, not even with a gigantic cabinet and porting. Looks to me like a measurement mistake, which can be easy to do in CEA-2010 testing, if you aren't scrupulous about the testing procedure.