The black SUB 18H Semi Horn-Loaded Active Class-D Subwoofer from dBTechnologies features a 18" woofer with a 4" voice coil, driven by a high-efficiency Digipro G3 Class-D digital amplifier with 1500W program and 2000W peak power. Thanks to the hybrid horn-loading configuration, the woofer can be tuned to the lowest frequencies, improving system efficiency and providing a deep, enveloping sound—even at close listening distance—which makes it suitable for small venues.