RCF SUB 905-AS II Powered Speaker. When compactn ess and loud sound levels are required simultaneously in subwoofer satellite systems, the SUB 905-AS II active subwoofer is the best option. The most cutting-edge RCF woofer technology is combined with a potent 2200 W digital amplifier in the SUB 905-AS. For transportable use by bands or DJs, it provides the ideal balance of bass reproduction, high SPL, and small dimensions.