the Alto Black 18 SUB is arguably one of the best powered subwoofers that I have ever used to date. I've used EV, JBL, Cerwin Vega, and many other top branded powered Subwoofers in my day and I can assure you that the Alto Black 18 SUB can definitely hold its own when compared among the rest. For starters, the Black 18S has a massive 1200 Watt continuous stream of power which vibrates and rattles your bones to the core. The build quality is great where the cabinet is solid and durable with a textured finish and steel reinforced rubber feet. The Bass is very deep and deeper than another (unnamed) Subwoofer that I have in the lab. The Bass is also responsive and tight and won't vibrate or produce feedback when its not supposed to. Just like with the rest of the Black series, the 18S has a DSP-Controlled Crossover that can be altered on the rear of the subwoofer or with an iOS device using the Live Drive App. The Black 18S also has two XLR/quarter-inch combo inputs and two XLR outputs.