This Speaker

Vanns.com has the Energy 8” 200W Powered Subwoofer - Black for $149.88 with free shipping.

Product description from Vanns.com:

Discover the decimal

You’ve seen a movie, right? You’ve even heard a movie before. But have you ever felt a movie’s soundtrack? It might seem innocent, that little “.1″ in 5.1- or 7.1-channel audio configurations, but it’s responsible for an entire dimension of your listening experience. While center- and surround-channel speakers reproduce vocals, dialogue, and surround sound effects, it’s the subwoofer that delivers deep, full, low-frequency bass audio. And because of its low-frequency properties, bass audio can be both heard and felt. Imagine the sound of racing e
ngines in your favorite action flick’s chase scene. Combining a 8″ active woofer driver with 200W of built-in amplification, the Energy ESW-8HD subwoofer is the difference between an engine that purrs and one that roars. Discover the difference the decimal can make in your home theater with an Energy subwoofer.

Bass reflex, it’s like an instinct

The design of a variety of a subwoofer’s components is essential to the woofer’s performance. As important as the design of the driver, amplifier, and circuitry is a sub’s enclosure, or cabinet. As a vented-enclosure subwoofer (also known as a bass-reflex sub), the Energy ESW-8HD allows you to experience enhanced low-frequency reproduction out of a smaller enclosure. Vented systems use the sound produced at the rear side of the driver’s diaphragm to increase the efficiency of the system at low frequencies by taking advantage of the resonance of ports or vents designed into the enclosure. The air mass in the cylindrica
l ports resonates in response to the movement of the air beh!
ind the
diaphragm within the enclosure, similar to the way that the air in a glass bottle resonates when you blow air across its mouth. Your new ESW-8HD’s vented design extends low-frequency bass performance and, simultaneously, allows for a more modest enclosure size that won’t dominate space in your living room.

Ribbed Elliptical Surround

The patented Ribbed Elliptical Surrounds encircling the Energy ESW-8HD’s active driver cone are unlike any other. Because the shape of the speaker surround has been changed to an ellipse, distortion is dramatically reduced. Further, the resulting increased excursion and larger piston area allow for greater efficiency. Finally, because Ribbed Elliptical Surround technology allows for larger cone surfaces and greater peak-to-peak cone movement, an incredible amount of air can be moved by the driver, ultimately making it possible to play lower frequencies with greater fidelity.

Psychoacoustics — Energy is crazy
about sound

Energy’s passion for and dedication to the reproduction of sound has a long history. Beginning back in the 1970s, Energy participated in nearly a decade of pioneering research into psychoacoustics, attempting to identify those measurable factors listeners associate with a “good-sounding” loudspeaker. Flat frequency response, wide dispersion, and low distortion, they concluded, were the primary factors influencing a listener’s perception of the realism of sound produced by a speaker. Consequently, Energy has spent the past thirty years furthering research and applying research-based principles to their engineering and manufacturing of high-performance loudspeakers for the home audio enthusiast.

Product link.