Description
Its Hybrid® horn/reflex loading combines the acoustic efficiency and impact of bass horn technology with the low frequency extension of a reflex design, enabling it to produce significantly higher output levels than a traditional reflex-loaded subwoofer. With an operating range of 32-150Hz ± 3dB, it features dual long-excursion 18” (460mm)/4.5” (115mm) voice coil neodymium drivers, with water resistant cones and triple roll surrounds.
The enclosure is constructed from multi-laminate plywood and coated with hard-wearing textured black paint. A rigid perforated steel grille protects the front of the enclosure. By using the integral flying hardware and the WPLGRIDt flying frame, you can fly arrays of SXHF218 subwoofers above WPL arrays or, more commonly, fly them alongside as a separate subwoofer array. Like the ground-stack version, a combination of forward and rear-facing enclosures can be configured with specific directional properties. By adding an outrigger kit, SXHF218 subs can be ground-stacked beneath WPL enclosures to form a powerful ground-based system.
The SXHF218 can be powered by either a single channel of a Martin Audio iK42 4-channel amplifier, or a bridged pair if maximum output is required. The connector sockets are wired so that one four-core cable from the amplifier will power two subwoofers. SXHF218 settings are determined by a predetermined parameter set in Vu-Net when used in conjunction with an iK42, or are available from the Martin Audio website when used with alternative amplifiers.
We provide this subwoofer with a set of four castors. A transit cover is available as an optional accessory.
From Q2 2026, the SXHF218 has front and rear LED indicators and adds a front‑mounted NL4 input connector, bringing the total to three NL4 connectors, including the two on the rear. Upgraded flying hardware, corrosion-resistant pins, a new grille and updated connectors allow this version to meet stringent environmental testing standards.
You can illuminate the LED indicators via Vu‑Net software to identify each enclosure on the circuit. The rear LED is intended for use in cardioid setups.
The third NL4 input connector on the front improves cabling for subwoofers used in cardioid configurations. For outdoor use, you no longer need a WRKIT, but you must seal all three NL4 sockets. Use the correct cable connectors (NLT4FX or NLT4FX‑BAG) for connected sockets and install Martin Audio weatherproof NL4 sealing plugs in unused sockets. This provides an IP rating of IP54 for the connections.