B-52 "18-220S 18"" 1000W Cast Frame Subwoofer Speaker "Multi-layer, precision-wound polyamide voice coils create superior electro-mechanical energy conversion Rigid, heat dissipating cast-aluminum or steel frames provide ultimate motor structure support Deep, bumped back plates allow the voice coil to reach maximum excursion without bottoming-out, resulting in deep bass Advanced cone materials with superior internal damping mean ultra-fast transient response and super-low distortion Tough, flexible surround with long-throw, positive-" "Rigid, heat dissipating cast-aluminum or steel frames provide ultimate motor structure support" "Deep, bumped back plates allow the voice coil to reach maximum excursion without bottoming-out, resulting in deep bass" Advanced cone materials with superior internal damping mean ultra-fast transient response and super-low distortion "Tough, flexible surround with long-throw, positive-roll design, control extreme cone excursion and is highly tear-resistant"