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. The SUB 18H Subwoofer offers stereo inputs with selectable link or crossover outputs, a crossover frequency switch at 90 or 120 Hz, a phase-inversion switch, and built-in delay up to 4.5 ms, which is adjustable in 0.5 ms steps. It features delay control that allows sound-alignment between the subwoofer and speaker. It also feature a mini USB Type-B port to update system firmware and retrieve a telemetry log file that provides information on abnormal events, usage time, and amplifier status. The unit uses SMPS technology auto-ranging digital power supply that allows operation on 110 or 220 VAC. The 28-/56-bit DSP with 24-bit/48 kHz A/D conversion allows you to control the audio crossover of the acoustic components, frequency response, limiter, and phase alignment. The unit's Hybrid Enclosure Technology housing features a birch plywood cabinet coated with PVC, aluminum heavy-duty handles for easy transportation, and polypropylene edges that protect it from scratching or impacts during transport. The subwoofer can be pole mounted using the M20 threaded mount plate on the top of the cabinet.