The Danley Sound Labs TH118 Tapped Horn Passive Subwoofer is a high-output, professional-grade subwoofer known for delivering exceptional bass performance from a relatively compact enclosure. Utilizing Danley's patented Tapped Horn technology, it achieves an efficiency and output level that often rivals conventional dual-18-inch front-loaded subwoofers, while requiring less physical space and amplifier power. This design "doubles up" the driver's output ability, resulting in a more powerful and linear response, especially at the lower end of its frequency range.