LINEAR 5 MK2 118 Sub HPA 18" Active Bass-Reflex Subwoofer 1500WAs the most powerful subwoofer in the LINEAR 5 MK II series, the Sub HPA with its rigid, high performance 18 inch woofer and its powerful amplifier offers significantly more energy in the low end range than any other subwoofer in the series. This allows for a particularly precise and powerful bass reproduction with extremely compact dimensions. It is therefore not only a suitable basis for the LINEAR 5 MK II 308 LTA mid high unit, but also a powerful