TotalSub? – The sub-d100 is TotalDAC's passive companion subwoofer to their d100 speaker so uses the same woofers and enclosure dimensions. "The external crossover connects from the main stereo amplifier to the subwoofer amplifier's XLR input. We recommend our Amp-1 in 1kW mono version." Each sub runs 2 x 12" neodymium-powered woofers in a sealed Baltic Birch ply enclosure with 98dB/m/W sensitivity and a -6dB/18Hz cut-off. It measures 32x47x118cm WxDxH and weighs 37kg without xover and amplifier.