Bottom Line The PB12-NSD is a true reference-grade sub at a super-affordable price, delivering flat response and high output all the way down to 20 Hz. It’s compact, nearly cubic shape makes it easy to fit into your listening room — or even better, to fit two into your living room, which will help reduce the effects of room acoustics and give you smoother bass for multiple listeners. There’s no question that you can find subs with higher maximum output, but whether or not you’ll be able to make use of that extra output in your home theater is a very relevant question indeed. Test Bench Frequency response 19 to 272 Hz ±3 dB Bass output, subwoofer (CEA-2010 standard) • Ultra-low bass (20-31.5 Hz) average: 111.0 dB 20 Hz 110.2 dB 25 Hz 110.8 dB 31.5 Hz 112.1 dB • Low bass (40-63 Hz) average: 118.1 dB 40 Hz 119.0 dB 50 Hz 120.3 dB 63 Hz 115.1 dB I took the frequency response measurement shown in the chart with the crossover disabled. I measured the subwoofer with a Clio FW analyzer in stepped sine mode using ground plane technique, with the sub on the ground and the microphone 2 meters from the front of the sub, and the measurement smoothed to 1/6th of an octave. SVS claims on its site that the frequency response measurement of this sub is “ruler flat,” and they’re pretty much right. I can’t recall seeing a sub with flatter response than this, although the Sunfire SDS-12 comes very close. One strange thing about this sub: The combined low-pass function of the crossover, driver and enclosure is roughly -10 dB/octave, which isn’t very steep. (SVS claims -12 db/octave.) I don’t know anyone who uses the internal crossover on their sub, but this isn’t one I’d want to use. The bass output, measured using the CEA-2010 method standard, is strong all the way down to 20 Hz. At all frequencies except 31.5 Hz, the sub’s output was dictated by the internal limiter circuit. It’s common to see a limiter functioning between 40 and 63 Hz, but uncommon to see one that functions at lower frequencies. This shows SVS is putting a premium on low distortion (i.e., clarity) rather than maximum output. For comparison, the Hsu VTF-15H delivered best case CEA-2010 averages of 123.2 dB (40-63 Hz) and 119.2 dB (20-31.5 Hz) — 5.1 and 8.2 dB more, respectively, than the PB12-NSD.