The Prima APBX 8 AS2 active subwoofer, with the 8-inch driver, features a dedicated high-performance amplification module that enhances all the passive box technologies, such as the 2S² (2 Sides / 2 Sounds) design, the Plug & Play terminal block and ultra-compact size. The amplification module, with power outputs of 250W RMS, is developed with he-li technology (high efficiency / low impedance), which thanks to the absence of the DC-DC voltage booster reaches the impressive 90% efficiency level, very close to the theoretical limit of the D-Class. New input stage DBT (Dynamic Bass Tracking) technology allows 100% use of the He-Li (High-Efficiency Low Impedance) amplifier power and to enjoy a tense and dynamic bass even at very high listening volumes. Eliminating the voltage booster was made possible thanks to the development of the new dual coil drivers, which inherit all the technological background of the Prima subwoofers, but differ for the ultra-low impedance. This feature ensures a perfect synergy with the He-Li (High-Efficiency Low Impedance) technology, maximizing the combination of amplifier, speakers, and sealed box, to obtain low, powerful, and crisp frequencies. The controls section is complete and provides an optimal regulation of the low-frequency emission in the car cabin. The Butterworth low pass filter at 12dB/Oct. with variable cut-off frequency (50-200 Hz) can be bypassed when used with an AP bit processor with pre-out output dedicated to the sub. The adjustable bass-boost control (0 ÷ 6 dB) at 45 Hz allows the user to emphasize the response on the lower side of the spectrum. The high-level speaker-in input on the multi-pole connector eases the integration with OEM audio systems while the low-level input on RCA is dedicated to the connection with after-market sources. The subwoofer automatic turn on/off function ART (Automatic Remote Turn-On) can be configured to be controlled by the source remote signal, by the voltage variation on the high-level input, or by the audio signal on both inputs. Phase control (0 - 180°) completes the equipment. The SSP (Sub Smart Plug) terminal block is provided with a single Plug&Play connector to be able to disconnect the box easily and safely.