QSC Active speakers The QSC K Series is quite simply the new standard in lightweight powered loudspeaker systems. Under the direction of Pat Quilter, QSC's team of amplifier engineers have created a new standard in Class D power modules unparalleled in the industry. Next, breaking from the traditional loudspeaker paradigm, all full-range models (K8, K10, K12) are fitted with the identical 1.75" high-frequency (HF) device for unparalleled performance, regardless of speaker size. Extensive digital signal processing (DSP) is employed throughout, providing levels of sonic clarity and total output that defy the system's size and weight. Premium-grade materials, advanced construction processes and multiple mounting and suspension options allow for a wide range of live and installed applications.