Need big sound, slamming bass and audiophile extension, but don’t want to see where it comes from? The ISW-4 in-wall subwoofer is for you. Two long-throw 200mm (8in) drivers allow it to move the large volumes of air needed for high-quality low-frequency output. The speaker is housed in its own sturdy back box for rock-solid stability and minimum sound bleed, and is powered by the SA250, a separate audiophile-standard 250W Class D amplifier.