RCF HD 12-A Powered Speaker. RCF is concerned with your audio. The brand-new D-Line MK4 speakers improve sound quality with the ground-breaking FiRPHASE processing, increase performance with a number of all-new transducers, and update the grille design to elevate the professional appearance. The sound is very clear at a distance and the SPL power is consistent at very high levels. The vocals sound natural. The idea behind the HD-Line was inspired by the touring business, and it combines all of RCF's professional sound expertise with the highest level of dependability and durability for usage in demanding situations when travelling. Turn up the volume and connect your mixer, device, or microphone to the speaker: true plug-and-play.