The B-1 subwoofer is the top of the range subwoofer under the Britannia Series. It has the larger 12′ woofer instead of the 10″ found in the B-2 and B-3 and have a 500W amp driving the woofer versus 300W and 200W in the B-2 and B-3 respectively. The B-1 does produce some really deep low end but does it a more “civil” manner unlike similar 12″ subs from Velodyne or JL Audio. If a refined low end is what you need (the B-1 is more widely use in a two channel audio setting than a home theater system, unless you get two or more to give you the bass volume) to add some bottom end oomph, the B-1 fits the bill nicely. Controls on the back allows some very fine tuning in terms of crossover so some experimentation in your room and system is needed to achieve that synergistic assimilation.
Cosmetically, the sub is in very nice shape. Minor scuff marks and dings here and there but nothing major. We just recently had the module assembly in the sub replaced with a new set from their service center so it is ready to soldier on for many more years to come. We do not have the original packaging so this big and hefty subwoofer has to ship freight or pickup from our store.