RCF HD 15-A Powered Speaker. In its class, the HD 15-A is a unique product. The expert compression driver's high-power voice coil and custom-designed dome provide remarkable vocal clarity and sound projection. An exceptionally linear response and a focused, deep low-frequency control are features of the 15" high power woofer. The sophisticated DSP that controls the amplifier, which has a 1400 watt output, also handles crossover, equalisation, FiRPHASE, soft limiting, and speaker protection.