The ESB HR 6 US P is an active amplified subwoofer from the Harmony series, specifically designed for underseat installation to save cabin space. It features a 165 mm (6.5") speaker with a Class D amplifier that delivers 250 W RMS and up to 500 W max power, ensuring a deep bass response across a frequency range of 20 Hz to 150 Hz. Measuring 220 x 190 x 76 mm, this compact unit fits discreetly into tight areas while maintaining a sensitivity of 92 dB. You can connect it using either low-level RCA or high-level inputs, and fine-tune the sound via the variable gain control, low-pass filter, bass boost, and phase control. An included remote control allows you to adjust the audio settings on the fly to suit your listening preferences.