SVS has the SB12-NSD at $400 and the PB12-NSD at $500 for their BF sale.
My understanding is they are discontinuing these two subs which is a shame in the sense that they are very capable for their sale prices.
However, I am not to quick to recommend them because they do not have adjustments to help tune them to your room like many competitors. However, if you have other means to tune the subs, this gets you serious performance at a bargain price!
Unrivaled subwoofer bang for the buck, the newly manufactured PB12-NSD’s low frequency extension and output outclasses subwoofers costing three time the price. A high excursion 12-inch composite driver and 400 watts RMS, 800 watts Peak Power Sledge amplifier housed in a ported box cabinet...
www.svsound.com