Martin Logan Dynamo 500 powered subwoofer in like-new condition, working perfectly. 10" high-excursion driver with a 120-watt amplifier in a compact sealed cabinet — MartinLogan's signature tight, musical, non-boomy bass that blends with real speakers instead of overpowering them.
Line-level and LFE inputs, adjustable crossover and phase, and it can even be converted from down-firing to front-firing. Small enough to hide, serious enough for both music and movies. From the brand audiophiles trust for electrostatics — their subs are built to the same standard.