The Martin Audio SX218 is a high-output dual 18” passive subwoofer designed for professional sound reinforcement systems where powerful, extended low frequency performance is required. It is suitable for live sound, touring, theatres, concert halls, clubs, houses of worship, arenas, corporate events and demanding fixed installations where strong bass output and low distortion are essential.

Built around two long-excursion 18” drivers with 4” voice coils, the SX218 delivers very high output levels with strong transient response and controlled low frequency performance. Each driver uses a water-resistant cone and triple roll surround, while the cabinet’s eight reflex ports provide a large frontal area to help reduce turbulent air noise at high output levels.

With 2000W AES power handling and 8000W peak capability, the SX218 is designed for systems requiring serious sub-bass impact and significant headroom. Its dual 8Ω driver configuration allows each driver to be powered individually, with the cabinet operated using suitable amplification and dedicated DSP processing. Correct amplifier matching, crossover configuration and limiter setup are important to achieve reliable performance and full system integration.

The SX218 has a frequency response of 35Hz–150Hz ±3dB, with low frequency extension down to 30Hz at -10dB. This makes it suitable for applications where deep bass extension and high SPL capability are both required. It can be used as a standalone subwoofer, stacked with additional units or configured in cardioid arrays when paired and processed correctly.

The cabinet is constructed from multi-laminate birch/poplar plywood and finished with a durable black Polyurea coating for professional touring and installation use. It includes four bar handles, skids with mating channels for stacking, an M20 pole mount insert, 24x M10 mounting points and fittings for optional accessories including castors, transit cover and weatherised connector protection.

The Martin Audio SX218 is a strong choice for professional systems requiring substantial dual 18” subwoofer performance, flexible deployment and robust cabinet construction. Its combination of deep low frequency extension, high power handling and installation-ready features makes it well suited to demanding live sound and fixed venue applications.