The E15X SUB is a high-performance subwoofer designed by d&b audiotechnik to expand the low frequency capabilities of E-Series loudspeaker systems in both fixed installation and mobile sound reinforcement environments. Engineered to deliver controlled and extended low-end response, the E15X SUB plays a critical role in enhancing the clarity and impact of full-range audio systems. It incorporates an internal passive crossover network, allowing it to operate in parallel with E12 or E12 D loudspeakers on a single amplifier channel. This enables system designers and audio professionals to increase low frequency headroom without requiring additional amplification resources. Alternatively, the E15X SUB can function in active mode, using a dedicated amplifier channel to supplement any loudspeaker from the E-Series range. Built with a durable marine plywood enclosure and finished with a robust protective coating, the E15X SUB is equipped for professional use in touring and installation settings. The cabinet includes ergonomic handles and an M20 threaded top flange to accommodate standard loudspeaker stands. The E15X SUB is also offered in Special Colour and Weather Resistant versions, the latter meeting IP55 standards to support reliable operation in changing outdoor conditions. With its combination of performance, flexibility, and rugged construction, the E15X SUB meets the demands of professional users across a range of audio applications.