The specs of the PB12-NSD says +/-3dB 18Hz-200hz anechoic extension, that's mean it goes up to 200hz?
Since sound differences of up to 3dB are not easily audible, this speaker's specs are telling you that in the range of 18Hz to 200Hz your ear won't easily detect any difference in sound volume output produced by this speaker. The speaker certainly will produce sound output above 200Hz - but as the frequency goes above 200Hz your ear may start to be able to detect that the output volume is dropping off.
Dolby Labs specs for the LFE channel are designed to limit the maximum frequency of sounds in the LFE channel to be around 120Hz. This means that any source material with an LFE channel is unlikely to have much in the way of sound frequencies above 120Hz, which is well within the frequency response range of your sub.
. I guess they make up for it soundwise. I just wish they would jazz up the cabinet a bit. Maybe throw some wood veneer or high gloss in. Or perhaps wrap it in a sock like speaker grill like those spiffy Definitive Supercubes.
