The D SERIES-PSP1 is a compact active loudspeaker that delivers rich, detailed sound in Decora-compatible wall or chassis mounts. The input accepts either a -10 dBV unbalanced or a +4 dBu balanced signal on the rear-panel detachable terminal block. Amplification is provided by a high-efficiency Class D power stage with audio filtering tailored for crisp, pleasant audio clarity. The high-efficiency Class D output stage produces negligible heat for all levels of expected voice or music modulation. The amplified output level is controlled by a front-panel volume control. The PSP1 includes an analog compressor/limiter that makes higher average sound output levels possible without clipping.