The ES12 is a powered subwoofer built around a forward-firing 12-inch long-throw woofer with a mineral-filled polypropylene cone. A Class D amplifier drives it, and two internal Power Ports vent the cabinet to limit turbulence, noise and distortion. The cabinet is narrow and the driver fires forward, so it can sit near walls or on a shelf.

Signal processing is handled by 32-bit floating-point DSP with group-delay-minimizing filters and precision limiters. Blending with the main speakers is done with an adjustable 4th-order lowpass filter (50-160 Hz) and Time-Smart Phase Control, which offers 360 degrees of adjustment around the lowpass setting in 45-degree steps shown on LED indicators. An auto-sensing power supply lowers consumption when the subwoofer is idle.

It connects by wire only: an LFE RCA input and a stereo line-level pair of RCA inputs. It has no Bluetooth or wireless feed, so it must be hard-wired to the receiver. It is available in black.