Bass reflex active subwoofer with 1200 watt Class D amplifier and DSP with app control The DBX active subwoofers offer state-of-the-art technology with the new Digital Signal Processor amplifier. The app control for the DSP gives the user full control over the parametric 8-band equaliser, subsonic filter, low bass filter, phase and time delay for perfect integration via the smartphone app. This allows all settings to be conveniently adjusted from the driver's seat.