Seems to have had a recent price drop. A more budget friendly option if you can't make the leap for an SVS sub:
10ā Front Firing Spun-Copper IMG Woofer
Digital Amplifier with 300w Peak Power
Volume, Loss Pass Crossover & Phase Control
Line Level/ LFE RCA Inputs
Black Wood Grain Vinyl Finish
37cm x 32cm x 42cm @ 10.9kgs
Only goes down to 32hz and is still ported at that. Decent price for new but I would suggest going used for an older SVS, M&K, REL, or similar. I personally have experience with an M&K V-75 MKII that would -3dB at about 30hz but was also sealed and so could be EQd to a solid 22hz -3dB by sacrificing some loudness. Also had an REL Q200E that was tiny but with the crossover at the minimum setting could go down to 27hz -3dB. The SVS or bigger M&Ks would be able to go much louder.