"When your first powered sub, in the ubiquitous "box" form factor, is a smash hit like the "old" PB12-ISD was (called the PB1-ISD upon its debut some years back), you understandably might leave well enough alone. In fact, we did for quite a while. Today's PB12-NSD is our oldest Powered Box design and was, (despite never being seriously challenged at the $600 price point), overdue for a fresh look and benefit from our years of refining audio packages.
So while the name stays the same (Powered Box, 12" - single NSD type woofer), just about everything about it is different from before, save that latest NSD woofer and our stalwart 325 watt BASH amp. While the look is different for this product, it's very familiar to SVS watchers."