USED HIGH-END SUBWOOFER. FILLS THE ROOM WITH EXCELLENT BASS. THIS SUB USED IN SPARE ROOM SO NOT USED MUCH. HARD TO FIND IN THIS CONDTIONSMALL ATMOS SPEAKER SHOWN IN PICTURE SITTING ON TOP NOT INCLUDED Ultra-Powerful 15-inch Subwoofer with PBK Room Correction Capability!Dynamo™ 1500X features advanced MartinLogan engineering including a 650 watt (1300 watt peak) amplifier and a 15-inch low distortion woofer with a powerful magnet structure to deliver huge excursion and output while preserving subtle bass detail. XLR, RCA, and 12-volt trigger inputs guarantee connection flexibility while simplifying system integration. Its standard down-firing configuration quickly (and easily) converts into a front-firing setup for those who prefer a hidden installation. With optional PBK room correction (sold separately) the Dynamo 1500X is guaranteed to sound exceptional in any room. Perfect Bass Kit (PBK) ReadyAlthough correct placement plays a key role in optimizing subwoofer performance, positioning a subwoofer often requires compromises. Not anymore, thanks to MartinLogans Perfect Bass Kit (PBK, sold separately). The Dynamo 1500X is MartinLogans first subwoofer to feature PBK room correction. PBK uses a computer and microphone to listen throughout the listening environment and tailor the subs performance to the unique acoustic properties of a room—resulting in clean, powerful bass down to 20Hz.Powerful, High-Excursion 15-inch WooferDynamo 1500X features advanced MartinLogan design concepts. A high-resolution, low-distortion 15-inch woofer delivers huge excursion and sound output while preserving minute bass details, all without a hint of distortion. The cone materials exceptional damping properties ensure the smooth, non-resonant response necessary for seamless blending with MartinLogan electrostatic panel and Folded Motion driver technologies.Unique Front-Firing, Down-Firing DesignPlacement flexibility is maximized by the subwoofers front-firing or down-firing options. When placed in a cabinet or other discreet location, the Dynamo 1500X subwoofer can easily convert from standard down-firing to front-firing orientation, with no tools or special skills required. A grill cover and 90-degree RCA adaptors are provided for use in front-firing applications. Further flexibility is afforded by custom energy transfer coupler (ETC™) spikes, which can enhance stability on thick carpets, or create tighter coupling between subwoofer and floor to enhance overall sound quality.Advanced Ultra-Efficient Amplifier Design and Inverse Mathematical Equalization (IME) FilterAn IME filter is derived from the inverse of the unfiltered driver response. Precision IME filtering yields extremely accurate low-frequency response—far superior to that provided by the simple second-order high-Q filters typically found in most subwoofers in this price range. The Dynamo 1500X delivers a true 650 watts of continuous power and 1300 watts peak. An energy-conscious design, the Dynamo Series amps consume only 10 watts in standby mode.Sealed Cabinet with Extensive Internal BracingAlthough ports are a convenient and cost-effective way of increasing low-frequency output, when used in small cabinets their reliance on resonant energy impairs bass quality. A compact, sealed subwoofer system minimizes transient-blurring group delay while maintaining smooth, consistent response, regardless of music or movie source material. The Dynamo 1500Xs cabinet is constructed from the finest composite material for acoustic integrity. Inside, critically placed structural cross-bracing acts as an excellent baffle for the woofer, while the added rigidity keeps cabinet-induced resonances and non-linearities to inaudible levels.Seamless System Integration—Engineered for Stereo and Home TheaterComprehensive signal connections along with low-pass filtering and phase control make the integration of Dynamo 1500X subwoofers into a multi-channel home theater or stereo music setup a simple and seamless process. The main left/right line-level inputs feed into a precision low-pass filter with a cut-off frequency variable from 35 to 150 Hz. For systems in which a surround processor supplies the crossover, the Dynamo Series offers a LFE input, via either XLR or RCA connections, which bypass internal filters. Additionally, a trigger input allows processors to turn the Dynamo 1500X on and off via a 12V trigger connection.Energy Transfer Coupler (ETC) SpikesThe Dynamo 1500X comes with custom ETC spikes which can be used in place of the feet to enhance stability on thick carpets, or create tighter coupling between subwoofer and floor to enhance overall sound quality.